diff --git a/tests/model_executor/guided_decoding/test_xgrammar_checker.py b/tests/model_executor/guided_decoding/test_xgrammar_checker.py
new file mode 100644
index 00000000000..b911e499339
--- /dev/null
+++ b/tests/model_executor/guided_decoding/test_xgrammar_checker.py
@@ -0,0 +1,149 @@
+# Copyright (c) 2025 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+# either express or implied. See the License for the
+# specific language governing permissions and limitations under the License.
+
+import json
+import sys
+import unittest
+from unittest.mock import MagicMock
+
+mock_torch = MagicMock()
+mock_xgrammar = MagicMock()
+
+sys.modules["torch"] = mock_torch
+sys.modules["xgrammar"] = mock_xgrammar
+
+from fastdeploy.engine.request import Request
+from fastdeploy.model_executor.guided_decoding.xgrammar_backend import XGrammarChecker
+
+
+def make_request(**kwargs) -> Request:
+    """
+    Construct a Request object with default fields and override with any provided keyword arguments.
+    This helper function simplifies creating Request instances for testing by
+    pre-filling common fields and allowing selective overrides.
+    """
+    base = dict(
+        request_id="req-1",
+        prompt="",
+        prompt_token_ids=[],
+        prompt_token_ids_len=0,
+        messages=[],
+        history=[],
+        tools=[],
+        system="",
+        sampling_params={},
+        eos_token_ids=[],
+        arrival_time=0.0,
+        guided_json=None,
+        guided_grammar=None,
+        guided_json_object=None,
+        guided_choice=None,
+        structural_tag=None,
+        pooling_params={},
+    )
+    base.update(kwargs)
+    return Request(**base)
+
+
+class TestXGrammarChecker(unittest.TestCase):
+    def setUp(self):
+        self.checker = XGrammarChecker()
+
+    def test_guided_json_valid(self):
+        """
+        Test that a valid guided_json passes the schema check.
+        """
+
+        request = make_request(guided_json={"type": "string"})
+        request, err = self.checker.schema_format(request)
+        self.assertIsNone(err)
+        self.assertIsInstance(request.guided_json, str)
+
+    def test_guided_json_object(self):
+        """
+        Test that guided_json_object generates a JSON object type.
+        """
+
+        request = make_request(guided_json_object=True)
+        request, err = self.checker.schema_format(request)
+        self.assertIsNone(err)
+        self.assertEqual(request.guided_json, '{"type": "object"}')
+
+    def test_guided_grammar_valid(self):
+        """
+        Test that a valid guided_grammar passes the schema check.
+        """
+
+        request = make_request(guided_grammar='root ::= "yes" | "no"')
+        request, err = self.checker.schema_format(request)
+        self.assertIsNone(err)
+        self.assertIn("root", request.guided_grammar)
+
+    def test_guided_choice_valid(self):
+        """
+        Test that a valid guided_choice is correctly converted to EBNF.
+        """
+
+        request = make_request(guided_choice=["yes", "no"])
+        request, err = self.checker.schema_format(request)
+        self.assertIsNone(err)
+        self.assertIn("yes", request.guided_grammar)
+        self.assertIn("no", request.guided_grammar)
+
+    def test_guided_choice_invalid(self):
+        """
+        Test that an invalid guided_choice (containing None) raises TypeError.
+        """
+
+        request = make_request(guided_choice=[None])
+        with self.assertRaises(TypeError):
+            self.checker.schema_format(request)
+
+    def test_structural_tag_valid(self):
+        """
+        Test that a valid structural_tag passes the schema check.
+        """
+
+        structural_tag = {
+            "structures": [{"begin": "<a>", "schema": {"type": "string"}, "end": "</a>"}],
+            "triggers": ["<a>"],
+        }
+        request = make_request(structural_tag=json.dumps(structural_tag))
+        request, err = self.checker.schema_format(request)
+        self.assertIsNone(err)
+
+    def test_structural_tag_invalid(self):
+        """
+        Test that a structural_tag missing 'triggers' raises KeyError.
+        """
+
+        structural_tag = {"structures": [{"begin": "<a>", "schema": {"type": "string"}, "end": "</a>"}]}
+        request = make_request(structural_tag=json.dumps(structural_tag))
+        with self.assertRaises(KeyError):
+            self.checker.schema_format(request)
+
+    def test_regex_passthrough(self):
+        """
+        Test that regex is not modified by schema_format and passes through as-is.
+        """
+
+        request = make_request()
+        request.regex = "^[a-z]+$"
+        request, err = self.checker.schema_format(request)
+        self.assertIsNone(err)
+        self.assertEqual(request.regex, "^[a-z]+$")
+
+
+if __name__ == "__main__":
+    unittest.main(verbosity=2)