Abstract: The Qinghai-Tibet Plateau is a sensitive region to climate change and grassland is the most widely distributed vegetation there. It is important to study the dynamics and trends of carbon in grassland ecosystem for understanding the impact of carbon on climate change. In this study, plant carbon, litter carbon, soil carbon and total carbon in Wudaoliang grassland ecosystem in the Qinghai-Tibet Plateau from 1961 to 2015 were simulated using BIOME-BGC model with localized parameters. The results showed that: (1) soil organic carbon was the main component of total carbon, accounted for 95% of total carbon sequestration, litter carbon and plant carbon was 4% and 1%, respectively; (2) the total carbon decreased slightly from 1961 to 2015 with a rate of -0.018%/a; plant carbon increased significantly with a growth rate of 0.187%/a; litter carbon decreased in these years, but there was a marked hysteresis to climate change; soil organic carbon (SOC) decreased ( -0.019%/a) with the increase of soil respiration rate due to warming, but its variation was small because of its strong resistance to external disturbance. The results indicate that warming leads to the increase of vegetation carbon, however, enhanced soil respiration causes a reduction in soil organic carbon and offsets the increase in vegetation carbon. As a result, warming leads to the decrease of total carbon.