In the fields of aviation, aerospace,shipbuilding,etc.,there are a large number of welding manufacturing requirements for small amount,flexible components that lack computer geometric models,for which model-based offline automatic programming systems are unsuitable. In response to this situation,a model-free robot automatic programming system for large complex components is designed.Through rapid 3D reconstruction of the processed components and analysis based on the 3D reconstruction results,the machining plan is pre-planned and the robot program is automatically generated. The deviation between the geometric model and the actual component is measured by the sensor,and the robot program is corrected online. The experiment results show that the system can analyze the large complex components lacking models online,and complete the corres-ponding welding tasks without the aid of work fixtures,providing a technical basis for the further automation of the robot processing.