Abstract: The trajectory planning method for electric vehicle in complex dynamic obstacle environment is an important research of electric vehicle intelligent auxiliary driving technology. In order to make the electric vehicle running and steering steadily under a high speed driving condition, an improved genetic algorithm based trajectory planning method was introduced to optimize the generated trajectory. First, the quintic polynomial curve was used to generate a trajectory. Then, the improved genetic algorithm was used to optimize the parameters of quintic polynomial curve, making the parameterized trajectory satisfy the dynamic constraints. The real vehicle experiment results show that, the optimized trajectory can adapt the dynamic constraints rather than the pre-optimized trajectory, and can make the electric vehicle steering steadily under high speed driving condition.