diff --git a/contrib/custom_analyzer_demo/README b/contrib/custom_analyzer_demo/README
index f5658fa4a95e21d81da4bf54db7779ca9e37f1de..10d941a06ee24ec1e1b5a557fbb17589d4112491 100644
--- a/contrib/custom_analyzer_demo/README
+++ b/contrib/custom_analyzer_demo/README
@@ -1,3 +1,28 @@
+## Introduction
 This is a demo to show how to implement an custom analyzer for openGauss.
 This demo changes the logic of check_ungrouped_columns_walker, in order to support syntax like SELECT a, b FROM t1 GROUP BY a; which is not supported by original openGauss.
-The main logic is to implement an custom AnalyzerRoutine. Check function transformStmt for more details.
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+The main logic is to implement an custom AnalyzerRoutine. Check function transformStmt for more details.
+
+## Installation
+Copy custom_analyzer_demo directoty to openGauss-server/contrib and make.
+```
+cp contrib/custom_analyzer_demo /YOUR_PATH/openGauss-server/contrib -r
+cd /YOUR_PATH/openGauss-server/contrib
+make && make install
+```
+
+## Use extension
+Connect to gaussdb and create extension.
+```
+CREATE EXTENSION custom_analyzer_demo;
+```
+
+## Test the extension
+```
+CREATE TABLE t1(a int, b int);
+INSERT INTO t1 values(1,1),(2,2),(3,3),(1,66),(2,88);
+SELECT a, b FROM t1 GROUP BY a; --- report error
+
+SET custom_analyzer_demo.enable_custom_analyzer to true;
+SELECT a, b FROM t1 GROUP BY a; --- success
+```
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