The changes of plant biomass allocation patterns reflect the adaptation strategies of plants under different environmental conditions. Under the future climate warming, plant production and biomass allocation will change significantly in the alpine ecosystems of the Qinghai-Tibet Plateau. However, up to date, little information has been available on the plant biomass allocation and its responses to climate warming in the alpine scrubland on the eastern Qinghai-Tibet Plateau. In order to investigate the effects of climate warming on plant biomass allocation patterns of the alpine scrubland, open top chambers (OTC) were employed to simulate warming in this study. We examined the effects of the simulated warming on the plant biomass allocation patterns of shrub, herbaceous layer and community level of the typical Sibiraea angustata alpine scrubland on the eastern Qinghai-Tibet Plateau. The results showed that the simulated warming increased the air temperature and soil surface temperature by 0.6 ℃ and 1.2 ℃, respectively, but decreased soil surface water contents by 2.7% throughout the whole growing season. Simulated warming significantly increased the aboveground biomass of herbaceous layer and community level by 57.8% and 7.2%, respectively, as well as significantly increased the root biomass of shrub, herbaceous layer and community level by 42.5%, 105.6% and 45.6%, respectively. However, the simulated warming did not significantly affect the aboveground biomass of shrub layer. Simultaneously, the simulated warming not only significantly increased the total biomass of shrub, herbaceous layer and community level by 25.6%, 85.7% and 28.4%, respectively, but also significantly increased the root:shoot ratios of those by 33.2%, 30.4% and 36.0%, respectively. The results implied that the simulated warming promoted plant biomass production, and also significantly increased the proportion of plant biomass allocation to belowground roots in these alpine scrub ecosystems. Moreover, Pearson correlation analysis revealed that plant biomass allocation of alpine scrubland was significantly and positively correlated with air temperatures, soil temperatures and soil nitrite nitrogen contents. Multiple linear regression analysis also showed that air temperatures, soil temperatures, and soil nitrate nitrogen contents explained more than 50.8% of the variation of plant biomass allocation in the alpine scrubland. The results indicated that plants in these alpine scrubland could adapt to future climate warming by modulating their biomass allocation patterns on the eastern Qinghai-Tibet Plateau.