In the context of park city development, this paper explores the practical needs of combining urban construction with urban transportation system, and studies the formal semantic logic of the decoration design of trams. Under the guidance of the park city concept, the paper sorts out tram decoration design cases and relevant documents, investigates the current situation of tram decoration design at home and abroad, analyzes the existing problems of its decoration design for the construction of urban civilization, and summarizes the tram decoration design method of park city. Taking the context characteristics of Chengdu Park City as an example, combined with the fuzzy comprehensive evaluation method, establish three value criticism standards:aesthetic, emotional and cultural, so as to select a set of the design scheme. The method theory summarized is applied to the tram appearance design construction practice, and a tram decoration design scheme for Chengdu Park City construction has been put forward, not only providing theoretical guidance for the overall image design, but also having a very positive practical significance to improve the park city concept and construction practice.