Abstract: Based on the IMS remote sensing snow products with 1 km resolution from 2015 to 2023, combined with DEM and meteorological data, this study analyzed the spatio-temporal variation characteristics of snow cover in the upper basin of Wudongde hydropower station, and the effects of meteorological elements, terrain and land use on snow cover ratio (SCR) and snow cover frequency (SCF). The results showed that the annual mean SCR in the basin was 16.43%, with obvious seasonal variation.,which was the most stable in winter and the least stable in summer. The annual average snow increase and melt durations were 107 days and 176 days, respectively. The phenomenan of snowfall and partial melting were frequent from November to the following April. The large runoff of spring snowmelt was concentrated in eastern Qinghai and northern Sichuan. Among meteorological elements, the most closely related to SCR was air temperature, which decreased with increasing temperature. The sunshine duration affected SCR indirectly. The snow accumulation process mostly occurred when precipitation was small, mostly when the total daily precipitation was less than 1mm. Among the geographical factors, the elevation was the domainn factor of the spatio-temporal distribution of snow cover, and the SCF of the same elevation followed the order: winter>spring>autumn>summer. However, the topographic slope and land use types had little effect on SCF. The temporal variation characteristics of snow water equivalent showed good consistency with those of SCR.