The response of vegetation to hydrothermal conditions varies significantly due to the spatial heterogeneity of ecosystems. In-depth exploration of their response and adaptation mechanisms is important for understanding the impact of regional climate change. In order to explore the relationship between vegetation and climate change on the Qinghai-Tibet Plateau for a long time, we constructed the vegetation time series of the Qinghai-Tibet Plateau from 1982 to 2020 based on the global inventory modeling and mapping studies (GIMMS) Normalized Difference Vegetation Index (NDVI) and moderate resolution imaging spectroradiometer (MODIS) NDVI data sets by Maximum Value Composition (MVC), pixel-by-pixel regression analysis and data fusion. The Mann-Kendall trend method was used to analyze the dynamic changes of vegetation over the Qinghai-Tibet Plateau in recent 40 years. The partial correlation and complex correlation analysis methods were used to explore the responses of vegetation to the changes of temperature, precipitation and radiation, while the main driving factors of vegetation dynamic changes were demarcated. The results show that:(1) in recent 40 years, the average NDVI of vegetation growing season on the Qinghai-Tibet Plateau increased significantly with an average growth rate of 0.006/10a, which was 0.005/10a before 2000 and 0.011/10a after 2000. The area where NDVI increased significantly accounted for 73.97% of the total area of the Qinghai-Tibet Plateau. They were mainly distributed in the north, west and south of the Plateau. The NDVI decreased significantly in the southeastern Qinghai-Tibet Plateau, accounting for 18.38% of the total area, where the altitude is relatively low and human activities are frequent. (2) The response of vegetation to hydrothermal conditions in the hinterland of the Qinghai-Tibet Plateau is more intense than that in the edge of the plateau, and the response threshold is obvious. The temperature is 2-11℃, the precipitation is 250-650 mm, and the radiation is 2900-3750 MJ/m². On the whole, except for forest and shrub, the response degree of all alpine vegetation types to precipitation is stronger than that of temperature and radiation. On the interdecadal scale, the positive effect of ecological engineering from 2001 to 2010 was the most obvious. (3) The growth of vegetation on the Qinghai-Tibet Plateau is driven by hydrothermal factors accounts for 55.95% of the total area. Among them, more than 42.72% of the areas are complementary driven by temperature, precipitation and solar radiation. 13.23% of the areas are driven by combination multiple hydrothermal factors. In addition, 44.05% of the areas are non-climate-driven. In space, different vegetation types showed different positive and negative responses to hydrothermal factors. The alpine vegetation in the northern part of the plateau is mainly driven by solar radiation. The arid and semi-arid grasslands in the plateau hinterland are mainly driven by precipitation. The meadows and thickets in the central and southern part of the plateau are mainly driven by temperature. The coniferous, broad-leaved and mixed forests on the southern edge of the plateau are slightly more affected by radiation and temperature.