In order to study the mechanism of Guanxi driving the new product development of small and medium-sized enterprises(SMEs) innovation, a moderated mediating effect model was constructed, and the questionnaire data from 275 manufacturing SMEs in the Yangtze river delta and the pearl river delta were used for hypothesis testing. It is found that the Renqing and Xinren dimensions of Guanxi can directly improve the performance of new products of SMEs, and Guanxi can also indirectly improve the performance of new products of SMEs by encouraging customers to participate in the development of new products of SMEs through information-providing or co-developing. At the same time, the dynamic environment could adjust the relationship between customer involvement and new product performance. When the environment is more dynamic, the effect of the two dimensions of customer involvement on new product performance would be enhanced.