For solving the technology problem of the pin which becomes more coarse and deformation in the process of riveting complex structure of rockshaft, a kind of exactitude molding die was designed in the manner of petals structure, and a new structure was optimized through calculating the riveting force. Then, the rockshaft punched and riveted process were simulated by dint of Deform-3D tools. Finally, the rationality of the die structure was validated by contrast experiment. The results show that the upsetting distortion of the rockshaft and pin roll is effectively controlled when riveting，the requirements of pin‘s diameter is satisfied，and the problem of riveting quality is solved.