Abstract: On the basis of the definition of wind power generation simultaneity factor, this paper proposed the concept of hydropower generation simultaneity factor, i.e., the proportion of the generating capacity of hydropower station in the installed generating capacity. The daily inflow and power generation capacity of hydropower stations in Sichuan Province from 2016 to 2018 were used to calculate the hydropower generation simultaneity factor of major river basins in Sichuan Province. The correlations between inflow and hydropower generation capacity, inflow and hydropower generation simultaneity factor, and the hydropower generation simultaneity factor between basins were analyzed. The results showed that:(1) From 2016 to 2018, the annual average hydropower generation simultaneity factor of Sichuan Province was 59%, the annual hydropower generation simultaneity factor of Yalong River, Dadu River and Minjiang River were more than 50%, while that of Jialing River was 40%.(2) The inflow of major hydropower stations and hydropower generating capacity of the whole basin in SichuanProvince showed same trends.(3) The hydropower generation simultaneity factor correlation coefficients between Dadu River and Minjiang River, Yalong River and Dadu River were 0.96 and 0.92 respectively, which was significantly higher than that between Yalong River and Jialing River(0.65).