Qinghai-Tibetan Plateau is the highest and largest plateau on earth, and almost 60% of its area is occupied by natural alpine grassland (alpine steppe and meadow). Owing to its unique climatic conditions, together with little human disturbance, it provides a unique opportunity to test the above-and belowground biomass allocation patterns and its response to meteorological factors. In the past, many studies have been conducted between above-and belowground biomass and environmental factors on alpine meadows in the Qinghai-Tibet plateau, but large uncertainties still exist owing to the difficulty determining belowground biomass. Therefore, the allocation between above-and belowground biomass is still a central issue in plant ecology. In this study, we examined seasonal and interannual variations in biomass based on long-term monitoring data sets. Moreover, a general regression analysis was applied to examine the relationship between above-and belowground biomass and meteorological factors. The results showed that (1) at a seasonal scale, the aboveground biomass showed a unimodal relationship from May to August, with a peak in August (345.7±27.01) g/m² that represented the net primary productivity of alpine meadows, which then decreased from August to September. Thebelowground biomass was relatively complex than the aboveground biomass, which increased from May to July and decreased rapidly in August; no significant difference was observed in the belowground biomass among these months. At an interannual scale, aboveground biomass showed a significant increased trend during 2005-2015, reaching a maximum in 2014(437.12±32.01) g/m². The belowground biomass was relatively stable during 2005-2015, but the year-to-year variations in belowground biomass was larger than that of the aboveground biomass(CV=24.30%); the 10-year average of belowground biomass was (2566.58±138.11) g/m²; (2)the photosynthetic products were mainly distributed in the belowground biomass, with 80% root biomass distributed in the 0-10 cm soil layer. In addition, the distributed fraction was relatively stable across all soil depths (0-10, 10-20, 20-30, and 20-40 cm) among months; (3) the air relatively humidity was the most important factor affecting aboveground biomass, whereas the belowground biomass was less affected by climatic factors. Our results suggest that the alpine meadow ecosystem has a high self-regulation ability against environmental factors, and the evolution of alpine meadows is subject to the interference of human activities rather than climate change.