Aiming at the defects of the existing mirror, by using the hyperbolic mirror design, the mirror is divided into the main view area and side view area (the main view area closes to the plane mirror, and the side view area is convex). In order to meet the demand of smooth transition for two regional mirror, a surface fitting model is set up to fit the complex surface by triangle based linear fitting the algorithm, thus the mirror surface shape optimization is realized. The optimization is mainly manifested in perspectives of those the visible area becomes larger, the blind area decreases, and the image distortion rate is small. During the transition of the transition line, the image is coherent and the image distortion rate around the body is below 3%.