diff --git a/python/rapidocr/inference_engine/__init__.py b/python/rapidocr/inference_engine/__init__.py
index ab1f42d..0ecdd4f 100644
--- a/python/rapidocr/inference_engine/__init__.py
+++ b/python/rapidocr/inference_engine/__init__.py
@@ -1,6 +1,3 @@
 # -*- encoding: utf-8 -*-
 # @Author: SWHL
 # @Contact: liekkaskono@163.com
-from .onnxruntime import OrtInferSession
-from .paddlepaddle import PaddleInferSession
-from .torch import TorchInferSession
diff --git a/python/rapidocr/inference_engine/base.py b/python/rapidocr/inference_engine/base.py
index c524820..ed4ca28 100644
--- a/python/rapidocr/inference_engine/base.py
+++ b/python/rapidocr/inference_engine/base.py
@@ -10,6 +10,7 @@ import numpy as np
 from omegaconf import DictConfig, OmegaConf
 
 from ..utils.logger import Logger
+from ..utils.utils import import_package
 
 cur_dir = Path(__file__).resolve().parent.parent
 MODEL_URL_PATH = cur_dir / "default_models.yaml"
@@ -29,21 +30,33 @@ def get_engine(engine_name: str):
     logger.info("Using engine_name: %s", engine_name)
 
     if engine_name == Engine.ONNXRUNTIME.value:
+        if not import_package("onnxruntime"):
+            raise ImportError("onnxruntime is not installed.")
+
         from .onnxruntime import OrtInferSession
 
         return OrtInferSession
 
     if engine_name == Engine.OPENVINO.value:
+        if not import_package("openvino"):
+            raise ImportError("openvino is not installed")
+
         from .openvino import OpenVINOInferSession
 
         return OpenVINOInferSession
 
     if engine_name == Engine.PADDLE.value:
+        if not import_package("paddleocr"):
+            raise ImportError("paddleocr is not installed")
+
         from .paddlepaddle import PaddleInferSession
 
         return PaddleInferSession
 
     if engine_name == Engine.TORCH.value:
+        if not import_package("torch"):
+            raise ImportError("torch is not installed")
+
         from .torch import TorchInferSession
 
         return TorchInferSession
diff --git a/python/rapidocr/utils/utils.py b/python/rapidocr/utils/utils.py
index 5e44a7e..4fa4830 100644
--- a/python/rapidocr/utils/utils.py
+++ b/python/rapidocr/utils/utils.py
@@ -1,6 +1,7 @@
 # -*- encoding: utf-8 -*-
 # @Author: SWHL
 # @Contact: liekkaskono@163.com
+import importlib
 from pathlib import Path
 from typing import Union
 
@@ -8,6 +9,14 @@ import requests
 from tqdm import tqdm
 
 
+def import_package(name, package=None):
+    try:
+        module = importlib.import_module(name, package=package)
+        return module
+    except ModuleNotFoundError:
+        return None
+
+
 def download_file(url: str, save_path: Union[str, Path], logger=None):
     if not Path(save_path).parent.exists():
         Path(save_path).parent.mkdir(parents=True, exist_ok=True)
diff --git a/python/setup.py b/python/setup.py
index 6e691bc..fd70ed8 100644
--- a/python/setup.py
+++ b/python/setup.py
@@ -58,7 +58,7 @@ setuptools.setup(
     project_urls=project_urls,
     license="Apache-2.0",
     include_package_data=True,
-    install_requires=read_txt("requirements_ort.txt"),
+    install_requires=read_txt("requirements.txt"),
     package_dir={"": MODULE_NAME},
     packages=setuptools.find_namespace_packages(where=MODULE_NAME),
     package_data={"": ["*.onnx", "*.yaml"]},