Abstract: Large- and medium-size reservoirs are the key foundation for hydropower generation. Studying their spatial distribution is of great significance to water resource allocation and carbon emission reduction. Based on 4748 such reservoirs in China, the spatial pattern characteristics and influencing factors were deeply explored from multiple scales by using spatial analysis method. The results show that these reservoirs have a general spatial distribution structure of multi-core center and ring distribution. The global Moran index is 0.155, indicating the characteristics of obvious spatial correlation. Hunan, Guangdong and Hubei are the provinces with the largest number of large and medium-sized reservoirs, accounting for 24.3% of the national total. More than 50% are located in the third tier with annual rainfall above 800 mm, and the larger number of reservoirs are distributed over the mountain and hill topography and the Yangtze River Basin. The number on the southeast side to the Hu Huanyong's population dividing line accounts for 80.7%; the eastern, middle and western economic belts feature a distribution of more in west and less in east, gathering in east and scattered in west. The spatial pattern is mainly affected by the amount of water resources, relevant laws and regulations, fixed asset investment, and other factors.

Key words: China, large and medium-size reservoirs, multi-scale, spatial pattern, influencing factors, National Water Network