###### Abstract  
Temperature and precipitation are important abiotic factors affecting net primary productivity (NPP) in grassland ecosystems. However, findings on how elevation influences the effects of these factors on NPP in alpine grasslands are not yet consistent. In addition, the impact of varied patterns of climate change on NPP sensitivity with elevation remain unclear. Therefore, alpine grassland on the Tibetan Plateau (TP) was selected to profile the spatial and temporal patterns of NPP from 2001 to 2022, and subsequently to reveal the effects of temperature and precipitation on the sensitivity of NPP with altitudinal gradient. The results showed that (1) 91% of the TP grassland experienced positive NPP trends, and the NPP trends followed a unimodal curve with elevation, with the largest mean value at 2500 m; (2) a positive correlation between precipitation and NPP dominated the grassland NPP up to an elevation of 3400 m, and a positive correlation between temperature and NPP dominated the grassland NPP above an elevation of 3400 m; (3) temperature, precipitation, and their interaction explained, on average, 21% of the temporal variation in the NPP of TP grassland, and the explanatory capacity decreased significantly with elevation; and (4) elevation, temperature, and precipitation variations together explained 35% of the NPP sensitivity of the TP grasslands. This study reveals the altitudinal characteristics of NPP in grasslands affected by climate, and reminds us to take elevation into account when carrying out grassland management. net primary productivity; climate change; elevation gradient; alpine grassland; Tibetan Plateau 202467546754  
Among the numerous weather-related environmental variables, temperature and precipitation have been proven to be important factors influencing global patterns of vegetation productivity [3]. Studies have suggested that annual temperature and precipitation together explain 38-63% of the total variation in global primary productivity of terrestrial ecosystems [10; 11]. The significance of temperature and precipitation on vegetation productivity at the regional scale is also well documented, e.g., temperature and precipitation together explain 48% of the variation in NPP in grassland ecosystems in Central Asia [12] and 24.3% of the variation in NPP in forest ecosystems in eastern China [13]. Alpine vegetation growing in harsh environments has been reported to be more susceptible to changes in temperature and precipitation [14; 15]. The continuous rise in temperature in alpine regions has led to significant impacts on the growth and reproduction of alpine vegetation, for example, the advanced flowering of alpine plants and the reduction of their populations [7]. With regard to vegetation productivity, the dominant conclusion is that temperature increase enhances alpine vegetation productivity. However, recent studies have found that the response of alpine vegetation to increasing temperature is gradually weakening, and that increasing temperatures can even lead to a decrease in vegetation productivity by increasing water stress in plants [16; 17]. There seems to be no consistent conclusion on whether increased precipitation promotes or suppresses vegetation productivity in alpine regions, and both findings have been reported [18; 19]. Thus, it is urgent to clarify the effect of temperature and precipitation on the growth of alpine vegetation. Climate effects on vegetation growth are related to specific environmental backgrounds [20]. This means that the effects of temperature and precipitation on vegetation growth are necessarily spatially variable, e.g., with latitude and with altitude. However, most of the current studies have only explored the spatial features of climate-influenced plant growth through vegetation indices such as NDVI and EVI, which give an indication of the vegetation status but do not quantitatively characterize vegetation productivity [1; 21].