diff --git a/MarkdigToc.sln b/MarkdigToc.sln
index 52dccfb..baacc8a 100644
--- a/MarkdigToc.sln
+++ b/MarkdigToc.sln
@@ -8,6 +8,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Build", "Build", "{25A1C149
 		.editorconfig = .editorconfig
 		.gitattributes = .gitattributes
 		.gitignore = .gitignore
+		changelog.md = changelog.md
 		global.json = global.json
 		License = License
 		Readme.md = Readme.md
diff --git a/Readme.md b/Readme.md
index 1371830..3413edd 100644
--- a/Readme.md
+++ b/Readme.md
@@ -1,6 +1,6 @@
 # MarkdigToc  [![NuGet](https://img.shields.io/nuget/v/Leisn.MarkdigToc)](https://www.nuget.org/packages/Leisn.MarkdigToc/)
 
-MarkdigToc is a extension for [Markdig](https://github.com/xoofx/markdig) to generate table of content by parse [toc] in markdown content. 
+MarkdigToc is a extension for [Markdig](https://github.com/xoofx/markdig) to generate table of content by parse [toc] in markdown document. 
 
 > Currently just for render to html.
 
@@ -123,11 +123,11 @@ Code copied from `AutoIdentifierExtension`, then added some code and options.
 
 #### TOC Title
 
-> NOTICE: I also parse toc title and use it's attributes from markdown content , but that is not a regular *syntax*, you should know that.
+> NOTICE: I also parse toc title and use it's attributes from markdown document , but that is not a regular *syntax*, you should know that.
 
 * `OverrideTitle`: `string? : default null`
 
-  Override toc title , ignore defined in markdown content.
+  Override toc title , ignore defined in markdown document.
 
 * `TitleTag`: `string : default p`
 
@@ -159,7 +159,7 @@ Code copied from `AutoIdentifierExtension`, then added some code and options.
 
 ## Others
 
-Markdown content:
+Markdown document:
 
 ```markdown
 [TOC]       
diff --git a/changelog.md b/changelog.md
new file mode 100644
index 0000000..6161bd3
--- /dev/null
+++ b/changelog.md
@@ -0,0 +1,6 @@
+### 0.1.3
+------
+
+* Fix parse two markdown document use same `MarkdownPipelineBuilder` , one document without `[toc]` and the other one has, the generated toc block will contains both. This bug is occur case I use the `TocOptions.Headings` to store the headings, and don't clear them when all renderer completed, not just clear after toc rendered.
+* After fixed, markdown document can has more than one `[toc]` , and all of these can be rendered, though it's useless.
+
diff --git a/src/HtmlTocRenderer.cs b/src/HtmlTocRenderer.cs
index 8e4aff0..1345084 100644
--- a/src/HtmlTocRenderer.cs
+++ b/src/HtmlTocRenderer.cs
@@ -65,9 +65,6 @@ protected override void Write(HtmlRenderer renderer, TocBlock obj)
                     renderer.Write($"</{Options.ContainerTag}>");
             }
             renderer.EnsureLine();
-
-            //once randerered clear the tree
-            Options.Headings.Clear();
         }
 
         void WriteTitle(HtmlRenderer renderer, TocBlock obj)
diff --git a/src/MarkdigToc.csproj b/src/MarkdigToc.csproj
index 70e7a51..1413a14 100644
--- a/src/MarkdigToc.csproj
+++ b/src/MarkdigToc.csproj
@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <OutputType>Library</OutputType>
@@ -10,15 +10,19 @@
 
   <PropertyGroup>
     <PackageId>Leisn.MarkdigToc</PackageId>
-    <VersionPrefix>0.1.2</VersionPrefix>
+    <Version>0.1.3</Version>
     <Authors>leisn</Authors>
     <PackageLicenseExpression>BSD-2-Clause</PackageLicenseExpression>
     <PackageTags>Markdown toc Markdig md md2html</PackageTags>
-    <Description>A extension for Markdig to generate table of content by parse [toc] in markdown content.</Description>
+    <Description>A extension for Markdig to generate table of content by parse [toc] in markdown document.</Description>
     <PackageReadmeFile>Readme.md</PackageReadmeFile>
     <PackageIcon>icon.png</PackageIcon>
-    <Copyright>Leisn</Copyright>
+    <Copyright>Copyright (c) Leisn 2021</Copyright>
     <PackageProjectUrl>https://github.com/leisn/MarkdigToc</PackageProjectUrl>
+    <PackageReleaseNotes> v0.1.3: 
+      1. Fix parse two markdown document use same `MarkdownPipelineBuilder` , one document without `[toc]` and the other one has, the generated toc block will contains both.
+      2. After fixed, markdown document can has more than one `[toc]` , and all of these can be rendered, though it's useless.
+    </PackageReleaseNotes>
   </PropertyGroup>
 
   <PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
diff --git a/src/TocExtension.cs b/src/TocExtension.cs
index e1b2fe4..7a938e0 100644
--- a/src/TocExtension.cs
+++ b/src/TocExtension.cs
@@ -1,8 +1,10 @@
 using Markdig;
 using Markdig.Renderers;
 using Markdig.Renderers.Html;
+using Markdig.Syntax;
 
 using System;
+using System.Linq;
 
 namespace Leisn.MarkdigToc
 {
@@ -28,22 +30,49 @@ public TocExtension(TocOptions options)
         //register parsers
         public void Setup(MarkdownPipelineBuilder pipeline)
         {
-            var cidE = pipeline.Extensions.Find<CustomAutoIdExtension>();
-            if (cidE == null)
+            var autoIdExtension = pipeline.Extensions.Find<CustomAutoIdExtension>();
+            if (autoIdExtension == null)
                 throw new InvalidOperationException("CustomAutoIdExtension is null");
-            cidE.OnHeadingParsed += (heading) => Options.AddHeading(heading);
+            autoIdExtension.OnHeadingParsed -= AutoIdExtension_OnHeadingParsed;
+            autoIdExtension.OnHeadingParsed += AutoIdExtension_OnHeadingParsed;
             pipeline.BlockParsers.AddIfNotAlready(new TocBlockParser(Options));
+
+            //clear headings after all rendered, not here
+            //pipeline.DocumentProcessed -= Pipeline_DocumentProcessed;
+            //pipeline.DocumentProcessed += Pipeline_DocumentProcessed;
         }
 
-        //register randerers
+        //private void Pipeline_DocumentProcessed(MarkdownDocument document)
+        //{
+        //    //if there is no [toc] in markdown document, clear the headings.
+        //    var tocBlocks = document.Where(block => block is TocBlock).ToList();
+        //    if (tocBlocks == null || tocBlocks.Count < 1)
+        //        Options.Headings.Clear();
+        //}
+
+        private void AutoIdExtension_OnHeadingParsed(HeadingInfo heading)
+            => Options.AddHeading(heading);
+
+        //register randerers, this method will execute after all parsers completed.
         public void Setup(MarkdownPipeline pipeline, IMarkdownRenderer renderer)
         {
             if (renderer is HtmlRenderer htmlRenderer)
             {
                 //because TocBlock:HeadingBlock ,so renderer must before HeadingRenderer
-                htmlRenderer.ObjectRenderers.InsertBefore<HeadingRenderer>(new HtmlTocRenderer(Options));
+                if (!htmlRenderer.ObjectRenderers.Contains<HtmlTocRenderer>())
+                    htmlRenderer.ObjectRenderers.InsertBefore<HeadingRenderer>(new HtmlTocRenderer(Options));
             }
+            
+            renderer.ObjectWriteAfter += Renderer_ObjectWriteAfter;
         }
 
+        private void Renderer_ObjectWriteAfter(IMarkdownRenderer arg1, MarkdownObject arg2)
+        {
+            //move HtmlTocRenderer -> Write -> 'Options.Headings.Clear()' to here
+            //now it can be more than one [toc] in markdown document , and all of these can be rendered
+            //though it's useless
+            if (arg2 is MarkdownDocument)// when the document all writed
+                Options.Headings.Clear();
+        }
     }
 }
diff --git a/src/TocOptions.cs b/src/TocOptions.cs
index 08c36cd..f38f9c8 100644
--- a/src/TocOptions.cs
+++ b/src/TocOptions.cs
@@ -63,7 +63,7 @@ public TocOptions()
         public string TocTag { get; set; } = "nav";
         /// <summary>
         /// Class names for toc element.<br/>
-        /// Notice: If also defined in markdown content , this will be auto add without repeating.<br/>
+        /// Notice: If also defined in markdown document , this will be auto add without repeating.<br/>
         /// e.g.<br/>
         /// <code>[toc] {.tocClass1.tocClass2}</code>
         /// <code>TocClass="toc tocClass1";</code>
@@ -73,7 +73,7 @@ public TocOptions()
         public string? TocClass { get; set; }
         /// <summary>
         /// Id for toc element.<br/>
-        /// Notice: If defined in markdown content , this will be <strong>ignored</strong>.<br/>
+        /// Notice: If defined in markdown document , this will be <strong>ignored</strong>.<br/>
         /// e.g.<br/>
         /// <code>[toc] {#tocId}</code>
         /// <code>TocId="tocId";</code>
@@ -124,6 +124,7 @@ public TocOptions()
         #endregion
 
         internal void AddHeading(HeadingInfo info)
-             => Headings.Append(HeadingInfos.FromHeading(info));
+            => Headings.Append(HeadingInfos.FromHeading(info));
+
     }
 }