diff --git a/api/core/workflow/nodes/question_classifier/question_classifier_node.py b/api/core/workflow/nodes/question_classifier/question_classifier_node.py
index 32f29a1c7c..139ad7e7e1 100644
--- a/api/core/workflow/nodes/question_classifier/question_classifier_node.py
+++ b/api/core/workflow/nodes/question_classifier/question_classifier_node.py
@@ -4,6 +4,8 @@ from typing import Optional, Union, cast
 from core.app.entities.app_invoke_entities import ModelConfigWithCredentialsEntity
 from core.memory.token_buffer_memory import TokenBufferMemory
 from core.model_runtime.entities.message_entities import PromptMessage, PromptMessageRole
+from core.model_runtime.entities.model_entities import ModelPropertyKey
+from core.model_runtime.model_providers.__base.large_language_model import LargeLanguageModel
 from core.model_runtime.utils.encoders import jsonable_encoder
 from core.prompt.advanced_prompt_transform import AdvancedPromptTransform
 from core.prompt.entities.advanced_prompt_entities import ChatModelMessage, CompletionModelPromptTemplate
@@ -129,7 +131,8 @@ class QuestionClassifierNode(LLMNode):
         :return:
         """
         prompt_transform = AdvancedPromptTransform(with_variable_tmpl=True)
-        prompt_template = self._get_prompt_template(node_data, query, memory)
+        rest_token = self._calculate_rest_token(node_data, query, model_config, context)
+        prompt_template = self._get_prompt_template(node_data, query, memory, rest_token)
         prompt_messages = prompt_transform.get_prompt(
             prompt_template=prompt_template,
             inputs={},
@@ -144,8 +147,49 @@ class QuestionClassifierNode(LLMNode):
 
         return prompt_messages, stop
 
+    def _calculate_rest_token(self, node_data: QuestionClassifierNodeData, query: str,
+                              model_config: ModelConfigWithCredentialsEntity,
+                              context: Optional[str]) -> int:
+        prompt_transform = AdvancedPromptTransform(with_variable_tmpl=True)
+        prompt_template = self._get_prompt_template(node_data, query, None, 2000)
+        prompt_messages = prompt_transform.get_prompt(
+            prompt_template=prompt_template,
+            inputs={},
+            query='',
+            files=[],
+            context=context,
+            memory_config=node_data.memory,
+            memory=None,
+            model_config=model_config
+        )
+        rest_tokens = 2000
+
+        model_context_tokens = model_config.model_schema.model_properties.get(ModelPropertyKey.CONTEXT_SIZE)
+        if model_context_tokens:
+            model_type_instance = model_config.provider_model_bundle.model_type_instance
+            model_type_instance = cast(LargeLanguageModel, model_type_instance)
+
+            curr_message_tokens = model_type_instance.get_num_tokens(
+                model_config.model,
+                model_config.credentials,
+                prompt_messages
+            )
+
+            max_tokens = 0
+            for parameter_rule in model_config.model_schema.parameter_rules:
+                if (parameter_rule.name == 'max_tokens'
+                        or (parameter_rule.use_template and parameter_rule.use_template == 'max_tokens')):
+                    max_tokens = (model_config.parameters.get(parameter_rule.name)
+                                  or model_config.parameters.get(parameter_rule.use_template)) or 0
+
+            rest_tokens = model_context_tokens - max_tokens - curr_message_tokens
+            rest_tokens = max(rest_tokens, 0)
+
+        return rest_tokens
+
     def _get_prompt_template(self, node_data: QuestionClassifierNodeData, query: str,
-                             memory: Optional[TokenBufferMemory]) \
+                             memory: Optional[TokenBufferMemory],
+                             max_token_limit: int = 2000) \
             -> Union[list[ChatModelMessage], CompletionModelPromptTemplate]:
         model_mode = ModelMode.value_of(node_data.model.mode)
         classes = node_data.classes
@@ -155,7 +199,7 @@ class QuestionClassifierNode(LLMNode):
         input_text = query
         memory_str = ''
         if memory:
-            memory_str = memory.get_history_prompt_text(max_token_limit=2000,
+            memory_str = memory.get_history_prompt_text(max_token_limit=max_token_limit,
                                                         message_limit=node_data.memory.window.size)
         prompt_messages = []
         if model_mode == ModelMode.CHAT: