diff --git a/src/Neo.Compiler.MSIL/Optimizer/NefInstruction.cs b/src/Neo.Compiler.MSIL/Optimizer/NefInstruction.cs
index 8e0551320..83d539fe0 100644
--- a/src/Neo.Compiler.MSIL/Optimizer/NefInstruction.cs
+++ b/src/Neo.Compiler.MSIL/Optimizer/NefInstruction.cs
@@ -78,10 +78,18 @@ public int GetAddressInData(int index)
             if (AddressSize == 0)
                 throw new Exception("this data have not Addresses");
 
-            byte[] buf = new byte[4];
-            Array.Copy(Data, AddressSize * index, buf, 0, AddressSize);
-            var addr = BitConverter.ToInt32(buf, 0);
-            return addr;
+            switch (AddressSize)
+            {
+                // 1 byte is stored as signed byte
+                case 1: return (sbyte)Data[index];
+                case 4:
+                    {
+                        byte[] buf = new byte[4];
+                        Array.Copy(Data, AddressSize * index, buf, 0, AddressSize);
+                        return BitConverter.ToInt32(buf, 0);
+                    }
+                default: throw new Exception("this data have not a valid address");
+            }
         }
 
         public void SetAddressInData(int index, int addr)
diff --git a/src/Neo.Compiler.MSIL/Optimizer/NefOptimizeTool.cs b/src/Neo.Compiler.MSIL/Optimizer/NefOptimizeTool.cs
index 4d46d3d47..c3871a2ff 100644
--- a/src/Neo.Compiler.MSIL/Optimizer/NefOptimizeTool.cs
+++ b/src/Neo.Compiler.MSIL/Optimizer/NefOptimizeTool.cs
@@ -47,21 +47,33 @@ public static byte[] Optimize(byte[] script, params OptimizeParserType[] parserT
                 optimizer.AddOptimizeParser(parser);
             }
 
-            //step01 Load
-            using (var ms = new MemoryStream(script))
-            {
-                optimizer.LoadNef(ms);
-            }
-            //step02 doOptimize
-            optimizer.Optimize();
+            bool optimized;
 
-            //step03 link
-            using (var ms = new MemoryStream())
+            do
             {
-                optimizer.LinkNef(ms);
-                var bytes = ms.ToArray();
-                return bytes;
+                //step01 Load
+                using (var ms = new MemoryStream(script))
+                {
+                    optimizer.LoadNef(ms);
+                }
+                //step02 doOptimize
+                optimizer.Optimize();
+
+                //step03 link
+                using (var ms = new MemoryStream())
+                {
+                    optimizer.LinkNef(ms);
+                    var bytes = ms.ToArray();
+
+                    optimized = bytes.Length < script.Length;
+                    if (optimized) { script = bytes; }
+                }
+
+                // Execute it while decrease the size
             }
+            while (optimized);
+
+            return script;
         }
     }
 }
diff --git a/tests/Neo.Compiler.MSIL.UnitTests/UnitTest_NefOptimizer.cs b/tests/Neo.Compiler.MSIL.UnitTests/UnitTest_NefOptimizer.cs
index eff5b734c..bcfa53a33 100644
--- a/tests/Neo.Compiler.MSIL.UnitTests/UnitTest_NefOptimizer.cs
+++ b/tests/Neo.Compiler.MSIL.UnitTests/UnitTest_NefOptimizer.cs
@@ -92,6 +92,28 @@ public void Test_Optimize_Recalculate_JMPNE_L()
             Test_Optimize_Recalculate_Positive_JMPX_L(VM.OpCode.JMPNE_L);
         }
 
+        [TestMethod]
+        public void Test_CombinedRules()
+        {
+            using (var scriptBefore = new ScriptBuilder())
+            using (var scriptAfter = new ScriptBuilder())
+            {
+                scriptBefore.Emit(VM.OpCode.PUSH1);
+                scriptBefore.Emit(VM.OpCode.NOP);
+                scriptBefore.Emit(VM.OpCode.PUSH0);
+                scriptBefore.Emit(VM.OpCode.NOP);
+                scriptBefore.Emit(VM.OpCode.EQUAL);
+                scriptBefore.Emit(VM.OpCode.PUSH0);
+                scriptBefore.Emit(VM.OpCode.EQUAL);
+
+                var optimized = NefOptimizeTool.Optimize(scriptBefore.ToArray(), OptimizeParserType.DELETE_USELESS_EQUAL, OptimizeParserType.DELETE_NOP);
+
+                scriptAfter.Emit(VM.OpCode.PUSH1);
+
+                CollectionAssert.AreEqual(scriptAfter.ToArray(), optimized);
+            }
+        }
+
         [TestMethod]
         public void Test_Optimize_Recalculate_BoolEqualTrue()
         {