In the context of global climate change, drought and extreme precipitation events will have far-reaching influences on species diversity and productivity of desert plant communities. Studying response mechanisms of plant communities to precipitation fluctuations is of great significance for the scientific management of desert ecosystems. By using rain shelters and drip irrigation systems to control precipitation input, this study evaluated the effects of extreme drought (decreasing precipitation by 50%, D1 treatment), drought (decreasing precipitation by 25%,D2 treatment) and increasing precipitation (increasing precipitation by 50%,W1 treatment; increasing precipitation by 25%, W2 treatment) on species diversity and biomass of desert plant communities. After one-year precipitation control experiments,we found that there was no significant difference in shrub and grass diversity indices, nor shrub biomass, under D1,D2, W1 and W2 treatments. The above-ground biomass of grass layers was sensitive to the precipitation changes. Grass biomass was (10.54 2.36) g/m~2 under D1 treatment, in contrast, grass biomass reached (105.69 28.60) g/m2 with 50% precipitation enhancement (W1 treatment). Grass biomass showed a linear increasing trend with precipitation enhancement and was significantly correlated with soil water content of the shallow layer (40cm depth, P<0.05). Therefore, biomass of grass layers were closely related to short-term (one year) precipitation fluctuations. Based on long-term location experiments, this study will further explore the effects of precipitation change on desert plant community characteristics,the results of which will provide data and theoretical support for response mechanism studies of desert ecosystems against the background of global climate change.