In order to meet the demand of lightweight and safety of the automotive seat, a design method for the carbon fiber composite material passenger car seat was proposed by using lightweight material and structural topology design optimization technology. The suggested new seat frame was composed of two parts, namely the carbon fiber laminate and short carbon fiber stiffener. In order to improve the stiffness and stability of the seat frame, the topology optimization method was used to arrange the layout of the stiffeners on the shell of carbon fiber laminate, and then the composite laminate optimization was implemented to improve the overall stiffness of the structure and reduce the weight of the frame. The results show that not only the overall stiffness of the new seat is raised, but also a significant reduction in weight about 30. 72% is achieved.