###### Abstract  
The eco-hydrological process related to vegetation on the Qinghai-Tibet Plateau is special, and the impact of snow cover on the growth of vegetation is unique and important. In this study, we analyzed the multi-year variations in the normalized difference vegetation index (NDVI) and snow cover on the Qinghai-Tibet Plateau from spatial and temporal perspectives and determined the relationship between the changes in the NDVI and snow cover. Results showed that in the last 40 years, the rate of change in the snow depth on the plateau was \(-0.016\) mm/a, and the NDVI changed by 0.0005/a. The correlations (!R! values) between the different factors and the NDVI followed the order of precipitation (0.77) \(>\) snow depth (0.76) \(>\) temperature (0.67) \(>\) solar radiation (0.21). The responses of the NDVI to changes in meteorological elements were synchronous, whereas the opposite was found for the snow cover. The snow cover had more significant impacts on vegetation at higher elevations. The NDVI had a lag of about 2 months from the onset of the snow cover, and heavy snow events had negative impacts on the NDVI for more than 3 years. Our findings will facilitate studies of ecological vulnerability and the predictions of changes in vegetation on the plateau. s 2024162140.11.  
studies of the global ecological issues caused by climate change. Therefore, the ecological and environmental issues that affect the QTP are attracting increasing attention. In general, it is considered that temperature and precipitation are the main climatic factors that affect the growth of vegetation [7], and studies have shown that the changes in vegetation on the QTP have prominent regional characteristics. The dominant factor that affects changes in vegetation in the semi-humid and semi-arid zones is the temperature, but the influence of precipitation on the changes in vegetation is significantly greater in the partially arid region than in the semi-humid and semi-arid zone [8]. The snow cover was low from the mid-1960s until the mid-1970s, but the snow cover on the plateau generally tended to increase from the late 1980s until the late 1990s, with a significant increase in the annual amplitude [9]. From the late 1990s until the present, the snow cover has tended to decrease significantly [10]. The impact of snow on vegetation is becoming increasingly evident due to the marked changes in the snow cover on the plateau. However, the mechanism that allows snow cover to affect vegetation on the QTP is complex, and various factors are involved [11]. First, altitude is an important limiting factor for vegetation growth, and studies have shown [12] that the negative correlation between snow and vegetation is more significant when the altitude is higher. Secondly, the indirect effects of snow-vegetation interactions also need to be considered. Snow melting can effectively recharge the soil and increase the soil moisture, which in turn affects vegetation [13]. Thirdly, with the unusual increase in the plateau temperature, the snow melting rate accelerates, and the factors of direct effects in the eco-hydroological processes have changed, which will comprehensively affect the indirect effects of snow on vegetation. Several previous studies have investigated the relationship between snow and vegetation [14; 15; 16; 17], as well as the effects of dynamic changes in snow and vegetation [6] on the QTP, but it is still unclear how various factors might affect snow and vegetation on the Plateau. In particular, few studies have investigated the positive and negative feedback between changes in vegetation and snow cover in different plateau areas and the factors (such as temperature, precipitation, solar radiation, soil moisture, etc.) involved. Therefore, in this study, we used month-by-month temperature, precipitation, solar radiation, and snow depth data for 40 years from 1981 to 2020 and week-by-week NDVI high-resolution plateau-wide raster data for the same period.