Aiming at the lateral safety problem when driving a car, it is proposed to introduce the BP neural network into the Lane Keeping Assistance System (LKAS) and combine it with the genetic algorithm to create a new BP neural network based lane keeping assistance system. In this article, firstly, the vehicle dynamics was modeled by vehicle dynamics, and then on this basis, the genetic algorithm was used to optimize the car. Finally, it is verified by simulation that compared with the traditional BP neural network, the BP system optimized by genetic algorithm has the smaller overshoot, faster responsiveness, and better guarantee the safety of driving.