diff --git a/agent/src/main/java/com/alibaba/testable/agent/handler/SourceClassHandler.java b/agent/src/main/java/com/alibaba/testable/agent/handler/SourceClassHandler.java
index 359ff78..6a7629e 100644
--- a/agent/src/main/java/com/alibaba/testable/agent/handler/SourceClassHandler.java
+++ b/agent/src/main/java/com/alibaba/testable/agent/handler/SourceClassHandler.java
@@ -39,7 +39,7 @@ public class SourceClassHandler extends BaseClassHandler {
         for (MethodNode m : cn.methods) {
             // record all member method names
             if (!ConstPool.CONSTRUCTOR.equals(m.name)) {
-                methods.add(new MethodInfo(cn.name, m.name, m.desc));
+                methods.add(new MethodInfo(cn.name, m.name, null, m.desc));
             }
         }
         // member methods which has injection stub
@@ -59,18 +59,23 @@ public class SourceClassHandler extends BaseClassHandler {
     private void transformMethod(ClassNode cn, MethodNode mn, Set<MethodInfo> memberInjectMethods,
                                  Set<MethodInfo> newOperatorInjectMethods) {
         AbstractInsnNode[] instructions = mn.instructions.toArray();
+        List<MethodInfo> memberInjectMethodList = new ArrayList<MethodInfo>(memberInjectMethods);
         int i = 0;
         do {
             if (invokeOps.contains(instructions[i].getOpcode())) {
                 MethodInsnNode node = (MethodInsnNode)instructions[i];
-                if (memberInjectMethods.contains(new MethodInfo(node.owner, node.name, node.desc))) {
-                    // it's a member method of current class and an inject method for it exist
+                int index = memberInjectMethodList.indexOf(new MethodInfo(node.owner, node.name, null, node.desc));
+                if (index >= 0) {
+                    // it's a member method and an inject method for it exist
                     int rangeStart = getMemberMethodStart(instructions, i);
                     if (rangeStart >= 0) {
                         if (cn.name.equals(node.owner)) {
+                            // member method of current class
                             instructions = replaceMemberCallOps(cn, mn, instructions, rangeStart, i);
                         } else {
-                            instructions = replaceCommonCallOps(cn, mn, instructions, node.owner, rangeStart, i);
+                            // member method of other class
+                            String method = memberInjectMethodList.get(index).getSubstitutionMethod();
+                            instructions = replaceCommonCallOps(cn, mn, instructions, node.owner, method, rangeStart, i);
                         }
                         i = rangeStart;
                     }
@@ -168,14 +173,14 @@ public class SourceClassHandler extends BaseClassHandler {
     }
 
     private AbstractInsnNode[] replaceCommonCallOps(ClassNode cn, MethodNode mn, AbstractInsnNode[] instructions,
-                                                    String ownerClass, int start, int end) {
+                                                    String ownerClass, String substitutionMethod, int start, int end) {
         mn.maxStack++;
         MethodInsnNode method = (MethodInsnNode)instructions[end];
         String testClassName = ClassUtil.getTestClassName(cn.name);
         mn.instructions.insertBefore(instructions[start], new FieldInsnNode(GETSTATIC, testClassName,
             ConstPool.TESTABLE_INJECT_REF, ClassUtil.toByteCodeClassName(testClassName)));
         mn.instructions.insertBefore(instructions[end], new MethodInsnNode(INVOKEVIRTUAL, testClassName,
-            method.name, addFirstParameter(method.desc, ownerClass), false));
+            substitutionMethod, addFirstParameter(method.desc, ownerClass), false));
         mn.instructions.remove(instructions[end]);
         return mn.instructions.toArray();
     }
diff --git a/agent/src/main/java/com/alibaba/testable/agent/model/MethodInfo.java b/agent/src/main/java/com/alibaba/testable/agent/model/MethodInfo.java
index 8906e94..68acfe1 100644
--- a/agent/src/main/java/com/alibaba/testable/agent/model/MethodInfo.java
+++ b/agent/src/main/java/com/alibaba/testable/agent/model/MethodInfo.java
@@ -5,13 +5,28 @@ package com.alibaba.testable.agent.model;
  */
 public class MethodInfo {
 
+    /**
+     * name of the class this method belongs to
+     */
     private final String clazz;
+    /**
+     * name of the method
+     */
     private final String name;
+    /**
+     * name of the substitution method
+     * Note: this field do NOT join the `equals()` or `hashCode()` calculation
+     */
+    private final String substitutionMethod;
+    /**
+     * parameter and return value of the method
+     */
     private final String desc;
 
-    public MethodInfo(String clazz, String name, String desc) {
+    public MethodInfo(String clazz, String name, String substitutionMethod, String desc) {
         this.clazz = clazz;
         this.name = name;
+        this.substitutionMethod = substitutionMethod;
         this.desc = desc;
     }
 
@@ -23,6 +38,10 @@ public class MethodInfo {
         return name;
     }
 
+    public String getSubstitutionMethod() {
+        return substitutionMethod;
+    }
+
     public String getDesc() {
         return desc;
     }
diff --git a/agent/src/main/java/com/alibaba/testable/agent/transformer/TestableClassTransformer.java b/agent/src/main/java/com/alibaba/testable/agent/transformer/TestableClassTransformer.java
index c1b9df6..2f3086d 100644
--- a/agent/src/main/java/com/alibaba/testable/agent/transformer/TestableClassTransformer.java
+++ b/agent/src/main/java/com/alibaba/testable/agent/transformer/TestableClassTransformer.java
@@ -86,12 +86,15 @@ public class TestableClassTransformer implements ClassFileTransformer {
                 String targetClass = getAnnotationParameter(an, TARGET_CLASS, sourceClassName);
                 String targetMethod = getAnnotationParameter(an, TARGET_METHOD, mn.name);
                 if (sourceClassName.equals(targetClass)) {
-                    methodInfos.add(new MethodInfo(toSlashSeparatedName(targetClass), targetMethod, mn.desc));
+                    // member method of the source class
+                    methodInfos.add(new MethodInfo(
+                        toSlashSeparatedName(targetClass), targetMethod, null, mn.desc));
                 } else {
+                    // member method of a common class
                     ImmutablePair<String, String> methodDescPair = extractFirstParameter(mn.desc);
                     if (methodDescPair != null && methodDescPair.left.equals(ClassUtil.toByteCodeClassName(targetClass))) {
                         methodInfos.add(new MethodInfo(
-                            toSlashSeparatedName(targetClass), targetMethod, methodDescPair.right));
+                            toSlashSeparatedName(targetClass), targetMethod, mn.name, methodDescPair.right));
                     }
                 }
                 break;