Abstract: The rational B-spline curve was introduced to obtain the forming trajectory for the wire arc additive manufacturing of thin-walled parts with complex curved surfaces. Firstly, the contour data were extracted according to the 3D model of the perform and the trajectory curve equation was established, then the forming path was automatically generated. Secondly, the offset of the performance in the z-axis direction was calculated by the edge curve equation, and the height compensation prediction was carried out to improve the layering accuracy and optimized the layering algorithm based on height prediction. Thirdly, aiming at the problem of high welding height at the intersection of thin-walled parts with intersection characteristics, the optimal path was designed based on the idea of an opposite and tangent forming path, and the error caused by stress concentration and heat accumulation can be minimized. Finally, the corresponding weld sizes under different welding parameters were obtained by experiments, and the suitable welding parameters range was determined. The feasibility of the optimization algorithm was verified by forming experiments of typical complex thin-walled structures. The results showed that the path planning optimization algorithm improved the layering accuracy and realized the layering algorithm optimization based on height prediction. At the same time, the surface of the solid part was well-formed, and the forming dimension error was within the acceptable range, so this algorithm can be applied in the process of preparing thin-walled structures.