diff --git a/src/Php/CompilerBase.php b/src/Php/CompilerBase.php
index c607faf6..265a8316 100644
--- a/src/Php/CompilerBase.php
+++ b/src/Php/CompilerBase.php
@@ -273,6 +273,11 @@ class CompilerBase extends \PhpAot\Core\Translator
         $this->formatCppCode($file);
     }
 
+    public function isScalarInt(Node\Expr $position): bool
+    {
+        return $position instanceof Node\Scalar\LNumber;
+    }
+
     public function getLine($node): int
     {
         return $node->getLine();
@@ -908,7 +913,7 @@ class CompilerBase extends \PhpAot\Core\Translator
         return self::LITERAL_STRINGS . '[' . $index . ']';
     }
 
-    protected function parseScalar(Node\Scalar $expr)
+    protected function parseScalar(Node\Scalar $expr): string
     {
         $type = $expr->getType();
         switch ($type) {
diff --git a/src/Php/Constants.php b/src/Php/Constants.php
index 1b41e3de..f199ca77 100644
--- a/src/Php/Constants.php
+++ b/src/Php/Constants.php
@@ -59,7 +59,5 @@ class Constants
     public const UNSUPPORTED_FUNCTIONS = [
         'compact',
         'extract',
-        'func_get_arg',
-        'func_get_args',
     ];
 }
diff --git a/src/Php/FuncCallOptimizer.php b/src/Php/FuncCallOptimizer.php
index c1b330fa..00f74a06 100644
--- a/src/Php/FuncCallOptimizer.php
+++ b/src/Php/FuncCallOptimizer.php
@@ -56,27 +56,74 @@ trait FuncCallOptimizer
         if ($name === 'array_key_exists') {
             return $getArg(1) . '.offsetExists(' . $getArg(0) . ')';
         }
+        if ($name === 'func_get_arg') {
+            return $this->genFuncGetArg($name, $expr);
+        }
         if ($name === 'func_get_args') {
-
+            return $this->genFuncGetArgs($name, $expr);
         }
         if ($name === 'func_num_args') {
+            return $this->genFuncNumArgs($name, $expr);
+        }
+        if ($name === 'function_exists') {
+            return $this->genFunctionExists($name, $expr);
+        }
+        return false;
+    }
+
+    public function genFuncGetArgs(string $name, Node\Expr\FuncCall $expr): string
+    {
+        $funcDef = $this->functionDef;
+        $list = [];
+        foreach ($funcDef->argInfoList as $i => $argInfo) {
+            if ($argInfo->variadic) {
+                $tmpVar = $this->addTmpVar(self::TYPE_ARRAY);
+                $this->context->beforeStmtLines[] = $this->genArray($list) . ';';
+                $this->context->beforeStmtLines[] = $tmpVar . '.merge(' . $argInfo->name . ');';
+                return $tmpVar;
+            }
+            $list[] = $argInfo->name;
+        }
+        return $this->genArray($list);
+    }
+
+    public function genFuncGetArg(string $name, Node\Expr\FuncCall $expr)
+    {
+        $position = $expr->args[0]->value;
+        if ($this->isScalarInt($position)) {
             $funcDef = $this->functionDef;
+            $posInt = intval($position->value);
             foreach ($funcDef->argInfoList as $i => $argInfo) {
                 if ($argInfo->variadic) {
-                    return '(' . $argInfo->name . '.count() + ' . $i . ')';
+                    return $argInfo->name . '.offsetGet(' . ($posInt - $i) . ')';
+                } elseif ($i == $posInt) {
+                    return $argInfo->name;
                 }
             }
-            return count($funcDef->argInfoList);
+            $this->fatalError($expr, 'wrong parameter position `' . $posInt . '`');
+        } else {
+            $this->fatalError($expr, 'func_get_arg() only support scalar int');
         }
-        if ($name === 'function_exists') {
-            $funcName = $expr->args[0]->value;
-            if ($this->isScalarString($funcName)) {
-                $funcName = $this->getLiteralString(strtolower(trim($funcName->value, '\\')));
-                return 'php::fn::function_exists(' . $funcName . ', true)';
+    }
+
+    protected function genFuncNumArgs(string $name, Node\Expr\FuncCall $expr): string
+    {
+        $funcDef = $this->functionDef;
+        foreach ($funcDef->argInfoList as $i => $argInfo) {
+            if ($argInfo->variadic) {
+                return '(' . $argInfo->name . '.count() + ' . $i . ')';
             }
-            return 'php::fn::function_exists(' . $this->parseIdentifier($funcName) . ')';
         }
+        return count($funcDef->argInfoList);
+    }
 
-        return false;
+    protected function genFunctionExists(string $name, Node\Expr\FuncCall $expr): string
+    {
+        $funcName = $expr->args[0]->value;
+        if ($this->isScalarString($funcName)) {
+            $funcName = $this->getLiteralString(strtolower(trim($funcName->value, '\\')));
+            return 'php::fn::function_exists(' . $funcName . ', true)';
+        }
+        return 'php::fn::function_exists(' . $this->parseIdentifier($funcName) . ')';
     }
 }
diff --git a/tests/aot/functions/func_get_arg.phpt b/tests/aot/functions/func_get_arg.phpt
new file mode 100644
index 00000000..73e2d5a1
--- /dev/null
+++ b/tests/aot/functions/func_get_arg.phpt
@@ -0,0 +1,29 @@
+--TEST--
+func_get_arg
+--FILE--
+<?php
+
+function foo1($a, $b, $c = 10)
+{
+    var_dump(func_get_arg(2));
+}
+
+function foo2(...$args) {
+    var_dump(func_get_arg(3));
+}
+
+function foo3($a, $b, $c, ...$args) {
+    var_dump(func_get_arg(4));
+}
+
+function main()
+{
+   foo1(2.5, 3);
+   foo2(1, 3, 5, 8, 10);
+   foo3(1, 3, 5, 8, 10, 12);
+}
+?>
+--EXPECT--
+int(10)
+int(8)
+int(10)
\ No newline at end of file
diff --git a/tests/aot/functions/func_get_args.phpt b/tests/aot/functions/func_get_args.phpt
new file mode 100644
index 00000000..6219fc7a
--- /dev/null
+++ b/tests/aot/functions/func_get_args.phpt
@@ -0,0 +1,54 @@
+--TEST--
+func_get_args
+--FILE--
+<?php
+
+function foo1($a, $b, $c = 10)
+{
+    var_dump(func_get_args());
+}
+
+function foo2(...$args) {
+    var_dump(func_get_args());
+}
+
+function foo3($a, $b, $c, ...$args) {
+    var_dump(func_get_args());
+}
+
+function main()
+{
+   foo1(2.5, 3);
+   foo2(1, 3, 5, 8, 10);
+   foo3(1, 3, 5, 8, 10, 12);
+}
+?>
+--EXPECT--
+array(3) {
+  [0]=>
+  float(2.5)
+  [1]=>
+  int(3)
+  [2]=>
+  int(10)
+}
+array(5) {
+  [0]=>
+  int(1)
+  [1]=>
+  int(3)
+  [2]=>
+  int(5)
+  [3]=>
+  int(8)
+  [4]=>
+  int(10)
+}
+array(3) {
+  [0]=>
+  int(8)
+  [1]=>
+  int(10)
+  [2]=>
+  int(12)
+}
\ No newline at end of file