Snow cover is an important component of the cryosphere. In recent years，climate warming has led to a reduction in snow cover area. This change may cause uneven distribution of water resources and a decline in biodiversity，thereby affecting local life，economic development and ecological environment. Qinghai Lake is the largest inland lake in China. In recent years，its water level has changed rapidly. The runoff into the lake is affected by the snow cover and its changes in the basin. However，the characteristics，changes and causes of the in‐ fluence of the snow cover in the Qinghai Lake Basin are still unclear. Based on the temperature and precipitation data from the Moderate-resolution Imaging Spectroradiometer（MODIS）daily cloudless 500 m snow area product Dataset and the China Meteorological Forcing Dataset（CMFD），This paper studies the spatial and temporal variation characteristics and influencing causes of snow cover in the Qinghai Lake Basin. The results show that： （1）There is a good correspondence between the distribution of the average annual snow cover frequency from 2000 to 2020 and the altitude. As the altitude decreases，the snow cover frequency also decreases accordingly. It is simultaneously affected by the average annual temperature and the annual precipitation. Among them，the areas significantly affected by the average annual temperature in a partial correlation are mainly distributed in the northern and eastern parts of Qinghai Lake，and the areas significantly affected by the annual precipitation in a partial correlation are mainly distributed in the middle and upper reaches of the Buha River in the middle of the Qinghai Lake Basin.（2）From 2001 to 2017，precipitation increased in the Qinghai Lake Basin and the Qilian Mountains region. However，due to the increase in the average annual temperature and the decrease in the annual snowfall in the two regions，the snow cover area decreased.（3）The intra-annual variations of snow cover area in the Qinghai Lake Basin and the Qilian Mountains region are relatively similar，both showing a double-peak fluctuation feature. However，the reduction in snow cover area from April to July and the increase from August to January of the following year in the Qinghai Lake Basin are both greater than those in the Qilian Mountains region. From January to March，the snow cover in the Qilian Mountains region decreased，while that in the Qinghai Lake Basin increased，which corresponds well to the lake effect after the melting of Qinghai Lake.