The bimetal plate is widely used because of its good performance. But the development of single point incremental forming is hindered by the processing defects that affect the accuracy and forming performance of parts such as bottom bulging and side wall bulging. The variations of forming accuracy of the single point incremental forming have been analyzed by using a combination of experiment method and finite element method. The results show that the bottom bulge height and the side wall bulging are most affected by the forming angle and forming depth respectively. These results indicate that the height of the bottom bulge is reduced by 29% and the side wall bulging is increased by 18.5% when the forming angle increases from 30°to 60°. The height of the bottom bulge is decreased by 13% and the side wall bulging is decreased by 16% when the tool head diameter is increased from 10mm to 20mm. The height of the bottom bulge is decreased by 24% and the side wall bulging is increased by 18.3% when the step down size from 0.2mm to 0.5mm. Finally, reasonable process parameters were optimized, so that the bottom bulge height decreased by 49%, and the side wall bulge decreased by 41%.