Understanding macro-scale spatial patterns in species richness and their underlying mechanisms is an important issue to macroecology and biogeography. Rosa species have a high economic and ecological value. Exploring the geographic patterns of species richness and their environmental determinants of Rosa in China will facilitate the resources protection and rational utilization, as well as systematic and evolutionary research of the genus. In this study, datasets of 15451 distributional records and 11 environmental factors were used to conduct species richness and correlation analyses. The results show that (1) Rosa is unevenly distributed in China. The species richness is the highest at latitudes ranging from 26.19°N to 34.29°N, and decreases as the latitude increase. The richness of Rosa is the highest at longitudes ranging from 99.10°E to 108.47°E, and decreased from this optimal range to the west and the east. The species richness shows unimodal pattern that increases first and then decreases with the increase of altitude, with the maximum value between 956.46 m and 3518.60 m. The central aggregation areas are located in the mountain areas around Sichuan Basin as well as Hengduan Mountains, and Chang Bai Mountains region and northern Xinjiang are the local aggregation areas. (2) The energy, water and habitat heterogeneity are positively associated with species richness. In addition, there are negative correlations between species richness and environmental stability. The Rosa has higher species richness in regions with the suitable hydrothermal conditions, the steady climate, and the great habitat heterogeneity. (3) The relationship between the species richness and the environment factors basically supports the productivity hypothesis, the environmental stability hypothesis and the habitat heterogeneity hypothesis. However, the hypotheses cannot fully explain the species richness pattern of Rosa, which indicates that other factors such as historical environment, terrain, soil properties or human activity probably have played a role in shaping the richness pattern of Rosa species. (4) Water factors account for 34.6% (P<0.001) of the species richness patterns of Rosa, so water is the dominant factor, which might be determined by the evolutionary history, physiological adaptation and other reasons. Our results can provide valuable information for the classification, evolution, protection and exploitation of wild resources of the Rosa species.