Three cities (Wuhan, Xiangyang, and Yidu) were selected as samples of three typical sizes of cities (large, medium, and small) in China to study the spatial layout of retail stores. The authors analyzed the spatial characteristics of different types of retail stores and the influential factors of their spatial distributions using tools of spatial statistics, based on big data of retail stores from the Baidu map. The results show that the spatial distribution of retail stores in the large city of Wuhan shows the characteristics of multi-center and multi-layer, while Xiangyang, the medium-sized city, shows a single center layout, and Yidu, the small city, shows dispersed layout. The agglomeration levels of different types of retail stores show a sequence: integrated retail store > professional retail store > supermarket > special retail store. Population size, transportation accessibility, types of retailing, and green-space accessibility are the main factors which affect the spatial distributions of retail stores. The results can provide the scientific basis for spatial planning and optimization of retail stores in multiple sizes of cities.