As a positioning reference part for wing assembly, how to effectively reduce the deformation of wing parts and improve the machining accuracy has always been an important task. According to the accumulated data analysis of the part, its deformation is mainly reflected in the saber bend, length extension and flatness warpage. This paper proposes a control method for the flatness warping deformation of wing beam parts during processing. It is mainly based on the technological characteristics of aircraft wing beam parts to analyze the actual deformation data of parts on the production site, determine the deformation trend, deformation amount and main influencing factors of beam parts. Then by improving the processing plan and controlling the processing deformation, the deformation of beam parts can be reduced to achieve the purpose of improving accuracy. The results show that the flatness value of the parts in the process of machining can be effectively improved and the deformation of beam parts can be significantly improved by the method proposed in this paper.