Abstract: In order to reduce the error of pillow effect parameter drum bulge in single point incremental forming(SPIF), the forming process parameters were studied. In view of the process complexity of the pillow effect phenomenon, the orthogonal experiment was designed, and the numerical simulation of single point incremental forming process under various process parameters was carried out by using the finite element software. Taking the height of the specific position (that is, bulging)of the pillow effect phenomenon as the evaluation index, the experimental data were analyzed based on the weighted grey correlation analysis method. The influences of the forming height, sheet thickness, forming angle, layer feed, tool head diameter and part size process parameters on the forming geometric accuracy were studied.The optimal process parameters of single point incremental forming and the primary and secondary order of the influence on the evaluation index were obtained.The results show that using the weighted grey correlation analysis can effectively reduce the geometric error of the pillow effect of the target part and improve the forming accuracy.