diff --git a/examples/mix_chord/mix_chord.yaml b/examples/mix_chord/mix_chord.yaml
index caa44c573b..26d04852e1 100644
--- a/examples/mix_chord/mix_chord.yaml
+++ b/examples/mix_chord/mix_chord.yaml
@@ -21,7 +21,7 @@ algorithm:
     ppo_micro_batch_size_per_gpu: 4
     ngpus_trainer: 4
     train_batch_size_expert: 64
-    train_batch_size_usual: 256 # (40 batchsize * (1 - 0.2 expert_data_ratio)) * 8 repeat times
+    train_batch_size_usual: 256 # 32 batchsize * 8 repeat times
 model:
   model_path: /PATH/TO/MODEL/
   max_response_tokens: 10240
@@ -31,7 +31,8 @@ cluster:
   gpu_per_node: 8
 buffer:
   total_epochs: 4
-  batch_size: 40
+  batch_size: 32
+  train_batch_size: 320
   max_retry_times: 3
   max_retry_interval: 1
   explorer_input:
diff --git a/examples/mix_math/mix_math.yaml b/examples/mix_math/mix_math.yaml
index f2bea04fe8..11eafb6cc9 100644
--- a/examples/mix_math/mix_math.yaml
+++ b/examples/mix_math/mix_math.yaml
@@ -25,7 +25,8 @@ cluster:
   gpu_per_node: 8
 buffer:
   total_epochs: 10
-  batch_size: 40
+  batch_size: 32
+  train_batch_size: 320
   max_retry_times: 3
   max_retry_interval: 1
   explorer_input:
diff --git a/tests/trainer/trainer_test.py b/tests/trainer/trainer_test.py
index ae320dd709..cedf4c2983 100644
--- a/tests/trainer/trainer_test.py
+++ b/tests/trainer/trainer_test.py
@@ -456,3 +456,59 @@ def test_fully_async_mode(self, name, use_priority_queue):
     def tearDown(self):
         checkpoint_path = get_checkpoint_path()
         shutil.rmtree(os.path.join(checkpoint_path, "unittest"))
+
+
+class TestTrainerMIX(BaseTrainerCase):
+    def test_trainer(self):
+        """Test MIX algorithm."""
+        # gsm8k has 16 tasks, sft_for_gsm8k has 8 tasks
+        # total 4 steps, each step: read 4 tasks from gsm8k, 16 tasks from sft_for_gsm8k
+        self.config.algorithm.algorithm_type = "mix"
+        self.config.algorithm.repeat_times = 4
+        self.config.algorithm.sample_strategy = "mix"
+        self.config.algorithm.sample_strategy_args = {"expert_data_ratio": 0.5}  # rft=4*4 : sft=16
+        self.config.algorithm.policy_loss_fn = "mix"
+        self.config.buffer.batch_size = 4
+        self.config.buffer.train_batch_size = 32
+        self.config.buffer.total_epochs = 1
+        self.config.buffer.explorer_input.taskset = get_unittest_dataset_config("gsm8k")
+        self.config.synchronizer.sync_interval = 1
+        self.config.trainer.save_interval = 1
+        self.config.buffer.trainer_input.sft_warmup_dataset = get_unittest_dataset_config(
+            "sft_for_gsm8k"
+        )
+        self.config.buffer.trainer_input.sft_warmup_dataset.total_epochs = 8  # test this works
+        self.config.check_and_update()
+        self.config.buffer.trainer_input.experience_buffer.max_read_timeout = 20
+        self.config.trainer.trainer_config.trainer.max_actor_ckpt_to_keep = 2
+        both(self.config)
+        parser = TensorBoardParser(os.path.join(self.config.monitor.cache_dir, "tensorboard"))
+
+        # test rollout metrics
+        rollout_metrics = parser.metric_list("rollout")
+        self.assertTrue(len(rollout_metrics) > 0)
+        self.assertEqual(parser.metric_max_step(rollout_metrics[0]), 4)
+        self.assertEqual(
+            parser.metric_values("rollout/experience_count")[1], 16
+        )  # 16 rft experiences
+        # test actor metrics
+        actor_metrics = parser.metric_list("actor")
+        self.assertTrue(len(actor_metrics) > 0)
+        expert_metrics = parser.metric_list("actor/expert/")
+        self.assertEqual(parser.metric_max_step(expert_metrics[0]), 4)  # SFT
+        usual_metrics = parser.metric_list("actor/usual/")
+        self.assertEqual(parser.metric_max_step(usual_metrics[0]), 4)  # RFT
+        response_metrics = parser.metric_list("response_length")
+        self.assertTrue(len(response_metrics) > 0)
+        self.assertEqual(parser.metric_min_step(response_metrics[0]), 1)
+        self.assertEqual(parser.metric_max_step(response_metrics[0]), 4)
+        # test save checkpoint at last step
+        checkpoint_dir, step_num = get_checkpoint_dir_with_step_num(
+            checkpoint_root_path=self.config.checkpoint_job_dir,
+            trainer_type="verl",
+        )
+        self.assertEqual(step_num, 4)
+        self.assertTrue(len(os.listdir(os.path.join(checkpoint_dir, "actor"))) > 0)
+
+    def tearDown(self):
+        shutil.rmtree(self.config.checkpoint_job_dir)