Abstract: In view of the current situation that the deformation of aero-engine blades after milling results in poor consistency before NC array polishing, a blade grouping method based on deformation characteristics is proposed in this paper to improve the machining consistency of the blades in the same group. Firstly, the range and trend of bending and torsion deformation of batch milling blades were analyzed, and then the index based on principal component analysis(PCA)was determined, and then the limit of grouping was determined according to the requirements of subsequent polishing process. Finally, according to the deformation of the blades in each group, the array machining track of the blades is adjusted to complete the synchronous array polishing of multiple blades. The method was applied to the grouping of multiple blades and the array polishing experiment was carried out. The result shows that the deformation of the blades in the group in the bending direction could be controlled within 0.02 mm after the grouping, which could meet the requirements of the following array polishing. This method provides an effective solution for the classification of blades before machining.