Brake piston is a huge demand non straight wall cavity part for the typical automotive industry; the traditional processing method is machine processing, or preforming by cold extrusion, and then machining. In this paper, the combined cold precision forging method of cold extrusion and spinning was proposed, which might improve the overall performance of parts and reduce costs. The rigid plastic finite element model of cold extrusion and spinning was established to simulate the forming process. The results showed that the combined cold precision forging method was available to manufacture non-straight wall cavity piston.