diff --git a/.gitignore b/.gitignore
index f2341f7..be1a9aa 100644
--- a/.gitignore
+++ b/.gitignore
@@ -27,3 +27,6 @@ conf.yaml
 # coverage report
 coverage.xml
 coverage/
+
+# Temporary PPT content files
+ppt_content_*.md
diff --git a/tests/test_ppt_localization.py b/tests/test_ppt_localization.py
new file mode 100644
index 0000000..c2a5512
--- /dev/null
+++ b/tests/test_ppt_localization.py
@@ -0,0 +1,135 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
+"""
+Unit tests for PPT composer localization functionality.
+
+These tests verify that the ppt_composer_node correctly passes locale information
+to get_prompt_template, allowing for locale-specific prompt selection.
+"""
+
+import pytest
+
+
+class MockLLMResponse:
+    """Mock LLM response object."""
+    
+    def __init__(self, content: str = "Mock PPT content"):
+        self.content = content
+
+
+class MockLLM:
+    """Mock LLM model with invoke method."""
+    
+    def invoke(self, messages):
+        """Return a mock response."""
+        return MockLLMResponse()
+
+
+class TestPPTLocalization:
+    """Test suite for PPT composer locale handling."""
+    
+    def test_locale_passed_to_prompt_template(self, monkeypatch):
+        """
+        Test that when locale is provided in state, it is passed to get_prompt_template.
+        
+        This test verifies that ppt_composer_node correctly extracts the locale
+        from the state dict and passes it to get_prompt_template.
+        """
+        # Track calls to get_prompt_template
+        captured_calls = []
+        
+        def mock_get_prompt_template(prompt_name, locale="en-US"):
+            """Capture the arguments passed to get_prompt_template."""
+            captured_calls.append({"prompt_name": prompt_name, "locale": locale})
+            return "Mock prompt template"
+        
+        def mock_get_llm_by_type(llm_type):
+            """Return a mock LLM."""
+            return MockLLM()
+        
+        # Import here to ensure monkeypatching happens before module import
+        import src.ppt.graph.ppt_composer_node as ppt_module
+        
+        # Monkeypatch the functions
+        monkeypatch.setattr(
+            ppt_module,
+            "get_prompt_template",
+            mock_get_prompt_template
+        )
+        monkeypatch.setattr(
+            ppt_module,
+            "get_llm_by_type",
+            mock_get_llm_by_type
+        )
+        
+        # Create state with input and locale
+        state = {
+            "input": "hello",
+            "locale": "zh-CN"
+        }
+        
+        # Call the ppt_composer_node
+        result = ppt_module.ppt_composer_node(state)
+        
+        # Verify get_prompt_template was called with the correct locale
+        assert len(captured_calls) == 1, "get_prompt_template should be called once"
+        assert captured_calls[0]["prompt_name"] == "ppt/ppt_composer"
+        assert captured_calls[0]["locale"] == "zh-CN", \
+            "get_prompt_template should be called with locale 'zh-CN'"
+        
+        # Verify result structure
+        assert "ppt_content" in result
+        assert "ppt_file_path" in result
+    
+    def test_default_locale_fallback(self, monkeypatch):
+        """
+        Test that when locale is missing from state, default locale 'en-US' is used.
+        
+        This test verifies that ppt_composer_node falls back to the default locale
+        'en-US' when no locale is provided in the state dict.
+        """
+        # Track calls to get_prompt_template
+        captured_calls = []
+        
+        def mock_get_prompt_template(prompt_name, locale="en-US"):
+            """Capture the arguments passed to get_prompt_template."""
+            captured_calls.append({"prompt_name": prompt_name, "locale": locale})
+            return "Mock prompt template"
+        
+        def mock_get_llm_by_type(llm_type):
+            """Return a mock LLM."""
+            return MockLLM()
+        
+        # Import here to ensure monkeypatching happens before module import
+        import src.ppt.graph.ppt_composer_node as ppt_module
+        
+        # Monkeypatch the functions
+        monkeypatch.setattr(
+            ppt_module,
+            "get_prompt_template",
+            mock_get_prompt_template
+        )
+        monkeypatch.setattr(
+            ppt_module,
+            "get_llm_by_type",
+            mock_get_llm_by_type
+        )
+        
+        # Create state without locale (only input)
+        state = {
+            "input": "hello"
+        }
+        
+        # Call the ppt_composer_node
+        result = ppt_module.ppt_composer_node(state)
+        
+        # Verify get_prompt_template was called with the default locale
+        assert len(captured_calls) == 1, "get_prompt_template should be called once"
+        assert captured_calls[0]["prompt_name"] == "ppt/ppt_composer"
+        assert captured_calls[0]["locale"] == "en-US", \
+            "get_prompt_template should be called with default locale 'en-US'"
+        
+        # Verify result structure
+        assert "ppt_content" in result
+        assert "ppt_file_path" in result