Due to the features of complicated and dissymmetrical form, the radiator cover shall be gained through the side trimming and piercing by compound die with vertical trimming technology followed. The process property of the radiator cover was analyzed. The structure and working principle of trimming and piercing compound die for radiator cover were expounded. The interface between cam driver and slide block was composed by a vertical plane and a horizontal plane which coordinated the order of the side trimming and the vertical trimming. The production efficiency is improved and the die structure is optimized by using Nitrogen pump for driving stripper device