Scientific research on the spatio-temporal variation characteristics of surface vegetation GPP and its response to climate change is of great significance for in-depth understanding of terrestrial carbon cycle， evaluation of environmental quality of terrestrial ecosystems， and estimation of the ecological effects of future climate change. At present， most of the time series of GPP spatio-temporal changes on the Qinghai-Tibet Plateau are short and the spatio-temporal changes and characteristics of GPP are not deeply analyzed. Therefore， this study used linear trend detection methods to study the changes of GPP in the Tibetan Plateau between 2001 and 2019， and analyzed the response of this feature to topography and land types， while exploring the relationship between GPP and air temperature， precipitation and snow cover. The results show that the inter-annual trend of GPP on the Tibetan Plateau shows the distribution characteristics of low in northwest and high in southeast， with a maximum value of 0.23$\mathrm{g}\mathrm{C}?{\mathrm{m}}^{-\mathrm{2}}?{\mathrm{d}}^{-\mathrm{1}}$ and a minimum value of -0.125$\mathrm{g}\mathrm{C}?{\mathrm{m}}^{-\mathrm{2}}?{\mathrm{d}}^{-\mathrm{1}}$；From October to March， the inter-annual change trend of GPP in most regions is small. The inter-annual change trend and spatial heterogeneity of GPP in July is the largest， from -0.384$\mathrm{g}\mathrm{C}?{\mathrm{m}}^{-\mathrm{2}}?{\mathrm{d}}^{-\mathrm{1}}$ to 0.303$\mathrm{g}\mathrm{C}?{\mathrm{m}}^{-\mathrm{2}}?{\mathrm{d}}^{-\mathrm{1}}$，and gradually decrease from August to October. The interannual trend of GPP decreases with elevation increasing.The interannual trend of GPP south of 30° N decreases rapidly and north of 30°N increases slowly with latitude increasing. The increasing inter-annual change trend of cropland/natural vegetation mosaics type is largest， 0.034 8$\mathrm{g}\mathrm{C}?{\mathrm{m}}^{-\mathrm{2}}?{\mathrm{d}}^{-\mathrm{1}}$.The decreasing inter-annual change trend of closed shrublands is largest， 0.007 6$\mathrm{g}\mathrm{C}?{\mathrm{m}}^{-\mathrm{2}}?{\mathrm{d}}^{-\mathrm{1}}$.In the past 19 years， temperature has the largest contribution to the GPP， followed by precipitation， and by radiation again， the contribution of snow to the GPP is relatively weak.