This paper aims to summarize the appearance of urban rail transit vehicles, develop intelligent parametric design technology software, and help designers carry out rapid decoration and color matching design and preview the effect of the scheme. Based on the geometric characteristics of the front curve of urban rail vehicles, it was summarized and classified into five basic shapes. The secondary development technology was used to establish the exterior decoration design template of urban rail vehicles. At the same time, the interactive genetic algorithm color matching technology was used to realize rapid and automatic urban rail vehicles Color matching. Based on the graphic design software CorelDraw, a series of parametric urban rail vehicle templates were developed, which realized the parametric design in the two-dimensional plane, and realized the design scheme of the shape and color matching of the locomotives in batches. In the process of designing the decoration and color matching of urban rail vehicles, the use of intelligent design technology can more efficiently realize the presentation of schemes and the batch comparison of multiple schemes, which is conducive to improving the designer's design and decision-making efficiency, and avoids repeated decoration and color matching design. The mechanized operation steps improve the designer's design efficiency.