The carbon cycle of terrestrial ecosystem relates to global climate change and its regional response comprehensively. Therefore, it is an important part of climate changes research and the impact of human activities. As an important part of the Qinghai-Tibet Plateau, the Qinghai Plateau plays an important role in the global and regional climate and environmental changes. Therefore, it is of great significance to study the temporal and spatial variation of carbon source/sink of vegetation and the influence of climate factors in Qinghai Plateau. By using the soil respiration model and the improved Carnegie Ames Stanford Approach (CASA) model, combined with MODIS and meteorological data, we estimated the net ecosystem productivity (NEP) of the Qinghai Plateau from 2000 to 2015, analyzed the inter-annual spatial and temporal distribution, the inter-annual dynamics and the multi-year accumulation spatial distribution of vegetation NEP and carbon sink, calculated the coefficient variation of vegetation NEP. We quantitatively discussed the impact of precipitation and temperature on vegetation NEP. The results indicate that 1) during 2000 and 2015, the spatial distribution characteristics of the annual vegetation NEP are high in the east and the south, low in the west and the north, and gradually increase from the northwest to the southeast. The annual average of NEP is 128.40 gC m^-2a^-1. 2) There is a significant spatial distribution of vegetation NEP and the amount of carbon sinks between different ecological regions, the total carbon sink area accounts for about 73.11% of the total vegetation area in Qinghai Plateau, of which the Qilian Mountain Ecological Area and the Sanjiangyuan Ecological Area are the main carbon sink areas.3) From 2000 to 2015, the carbon sink function of vegetation in Qinghai Plateau is gradually enhanced, and the annual carbon sequestration is -3.2—64.42 TgC. And the inter-annual variation of the carbon sequestration increases stably. 4) Influenced by the combination of natural and human factors, the annual NEP of Qinghai Plateau shows a gradually improvement trend, with an average trend coefficient of 1.52, and the area where NEP increases accounted for 25.72% of the total vegetation area. 5) The spatial distribution of NEP variation coefficient in Qinghai Plateau is mainly low and medium fluctuation, and the stability is quite high. 6) The precipitation mainly promotes vegetation NEP accumulation, the temperature inhibits the accumulation of NEP. And the influence of temperature on NEP accumulation is dominant.