With the widespread use of cars in daily life, car bumpers have also attracted increasing attention. The plastic film on the car bumper has made outstanding contributions to preventing damage to the bumper during scratches and collisions. However, the existing plastic film materials cannot meet the high requirements of car bumpers, and material optimization design is needed. Based on a parameter optimization system, this paper proposed an optimization design method for plastic film on automotive bumpers. Firstly, the key parameters of the plastic film were determined, including thickness, density, elastic modulus, etc. Then, using multi factor experimental design, experimental data on key parameters of plastic film were constructed, and the key parameters of plastic film were optimized without losing the expected performance of the film. Through orthogonal experimental design and response surface methodology, experimental data collection and analysis of key parameters of plastic films were achieved, and then optimized design of key parameters of plastic films was carried out. The results showed that the optimized key parameters of the plastic film could effectively improve the protective ability and service life of the car bumper while ensuring the original performance, and improve the safety performance of the car.