The key of closed-loop simulation of vehicle handling stability is to establish a driver model which could adapt to complicated path. The driver’s preview path was divided into several segments. Lateral displacement and heading angle deviation were calculated. Vehicle steering motion was controlled based on deviation of heading angle and position, therefore the vehicle could follow any complex path. In order to obtain the control parameters of driver model, different driving mode was designed. Genetic algorithm was applied to optimize these control parameters. The co-simulation results of Carsim and Simulink showed that the optimized driver model could fulfill the conditions of complicated road. 