Abstract: Based on the entropy model, this article comprehensively evaluated the development and spatial distribution characteristics of RD industry in the Yangtze River Delta City Group. Moreover, based on regional theory and the theory of urban spatial structure, this paper discovered the law of spatial agglomeration and the characteristics of the regional difference. The results showed that the development of RD industry in the Yangtze River Delta City Group was still in the rising stage; the difference of development distribution and region feature was obvious, basically showing spindle structure; and the triangular space gradient has been formed in Shanghai, Nanjing and Hangzhou City vertex.