diff --git a/src/converters/strategies/GeminiConverter.js b/src/converters/strategies/GeminiConverter.js
index 0ae394a..41a9d06 100644
--- a/src/converters/strategies/GeminiConverter.js
+++ b/src/converters/strategies/GeminiConverter.js
@@ -232,6 +232,11 @@ export class GeminiConverter extends BaseConverter {
                          candidate.finishReason.toLowerCase();
         }
 
+        // 如果包含工具调用，且完成原因为 stop，则将完成原因修改为 tool_calls
+        if (toolCalls.length > 0 && finishReason === 'stop') {
+            finishReason = 'tool_calls';
+        }
+
         // 构建delta对象
         const delta = {};
         if (content) delta.content = content;
diff --git a/tests/gemini-converter.test.js b/tests/gemini-converter.test.js
index 466b562..aac0168 100644
--- a/tests/gemini-converter.test.js
+++ b/tests/gemini-converter.test.js
@@ -66,4 +66,25 @@ describe('GeminiConverter', () => {
         expect(result.choices[0].delta.tool_calls[1].index).toBe(1);
         expect(result.choices[0].delta.tool_calls[1].function.name).toBe('tool_two');
     });
+
+    test('toOpenAIStreamChunk sets finish_reason to tool_calls when tool calls are present and finishReason is STOP', () => {
+        const geminiChunk = {
+            candidates: [{
+                finishReason: 'STOP',
+                content: {
+                    parts: [{
+                        functionCall: {
+                            name: 'test_tool',
+                            args: {}
+                        }
+                    }]
+                }
+            }]
+        };
+
+        const result = converter.toOpenAIStreamChunk(geminiChunk, 'gemini-pro');
+
+        expect(result).not.toBeNull();
+        expect(result.choices[0].finish_reason).toBe('tool_calls');
+    });
 });