diff --git a/Matcher/DefineVariableMatcher.cs b/Matcher/DefineVariableMatcher.cs
index f3d9018..b3cbbe7 100644
--- a/Matcher/DefineVariableMatcher.cs
+++ b/Matcher/DefineVariableMatcher.cs
@@ -4,15 +4,28 @@ namespace Convention.RScript.Matcher
 {
     public class DefineVariableMatcher : IRSentenceMatcher
     {
+        private readonly Regex DefineVariableRegex = new(@"(string|int|double|float|bool|var)\s+([a-zA-Z_][a-zA-Z0-9_]*)\s*=\s*(.+)");
+        private readonly Regex DeclareVariableRegex = new(@"(string|int|double|float|bool|var)\s+([a-zA-Z_][a-zA-Z0-9_]*)");
+
         public bool Match(string expression, ref RScriptSentence sentence)
         {
-            Regex DefineVariableRegex = new(@"(string|int|double|float|bool|var)\s+([a-zA-Z_][a-zA-Z0-9_]*)");
-            var DefineVariableMatch = DefineVariableRegex.Match(expression);
-            if (DefineVariableMatch.Success)
             {
-                sentence.mode = RScriptSentence.Mode.DefineVariable;
-                sentence.info = new() { DefineVariableMatch.Groups[1].Value, DefineVariableMatch.Groups[2].Value };
-                return true;
+                var DefineVariableMatch = DefineVariableRegex.Match(expression);
+                if (DefineVariableMatch.Success)
+                {
+                    sentence.mode = RScriptSentence.Mode.DefineVariable;
+                    sentence.info = new() { DefineVariableMatch.Groups[1].Value, DefineVariableMatch.Groups[2].Value, DefineVariableMatch.Groups[3].Value };
+                    return true;
+                }
+            }
+            {
+                var DeclareVariableMatch = DeclareVariableRegex.Match(expression);
+                if (DeclareVariableMatch.Success)
+                {
+                    sentence.mode = RScriptSentence.Mode.DefineVariable;
+                    sentence.info = new() { DeclareVariableMatch.Groups[1].Value, DeclareVariableMatch.Groups[2].Value, null };
+                    return true;
+                }
             }
             return false;
         }
diff --git a/RScriptContext.cs b/RScriptContext.cs
index c312358..fe0b46d 100644
--- a/RScriptContext.cs
+++ b/RScriptContext.cs
@@ -16,7 +16,7 @@ namespace Convention.RScript
             /// </summary>
             Expression,
             /// <summary>
-            /// 定义变量, 格式: 类型 变量名
+            /// 定义变量, 格式: 类型 变量名 [=Expression]
             /// <para>类型支持: string, int, double, float, bool, var</para>
             /// <para>每层命名空间中不可重复定义变量, 不可使用未定义的变量, 不存在时会自动向上查找上级空间的变量</para>
             /// </summary>
@@ -166,38 +166,39 @@ namespace Convention.RScript
             // 定义变量
             var varTypeName = sentence.info[0];
             var varName = sentence.info[1];
+            var varInitExpression = sentence.info[2];
             Type varType;
             object varDefaultValue;
             {
                 if (varTypeName == "string")
                 {
                     varType = typeof(string);
-                    varDefaultValue = string.Empty;
+                    varDefaultValue = varInitExpression == null ? string.Empty : varInitExpression;
                 }
                 else if (varTypeName == "int")
                 {
                     varType = typeof(int);
-                    varDefaultValue = 0;
+                    varDefaultValue = varInitExpression == null ? 0 : parser.Evaluate<int>(varInitExpression);
                 }
                 else if (varTypeName == "double")
                 {
                     varType = typeof(double);
-                    varDefaultValue = 0.0;
+                    varDefaultValue = varInitExpression == null ? 0.0 : parser.Evaluate<double>(varInitExpression);
                 }
                 else if (varTypeName == "float")
                 {
                     varType = typeof(float);
-                    varDefaultValue = 0.0f;
+                    varDefaultValue = varInitExpression == null ? 0.0f : parser.Evaluate<float>(varInitExpression);
                 }
                 else if (varTypeName == "bool")
                 {
                     varType = typeof(bool);
-                    varDefaultValue = false;
+                    varDefaultValue = varInitExpression == null ? false : parser.Evaluate<bool>(varInitExpression);
                 }
                 else if (varTypeName == "var")
                 {
                     varType = typeof(object);
-                    varDefaultValue = new object();
+                    varDefaultValue = varInitExpression == null ? new object() : parser.Evaluate(varInitExpression);
                 }
                 else
                 {