in order to improve the passengers comfort, the human engineering was used in the high-speed train seats analysis. According to the natural physiological shape, the paper was adopted the polynomial regression method in order to obtain a better kinesiology seat back curve equation. The exterior point penalty function method was adopted to optimize the curve equation. The optimized result showed that the ride comfort was enhanced. The paper used two new mathematic method in ergonomic design, and improved the high-speed seat comfort.