[Objective] Effects of precipitation on shrub community structure and diversity in Ulanbuh Desert were researched to provide theoretical basis for vegetation conservation and sustainable use of plant resources. [Methods] The relationships between precipitation & community structure, and precipitation & plant species diversity were analyzed using quadrat and precipitation data collected from 2011 to 2013. [Results] Rainfall could significantly affect the numbers of community species and families for three typical shrub communities of Ceratoides latens, Sarcozygium xanthoxylon and Tetraena mongolica. The increases of species and families in the three communities listed as follows as precipitation increased. The numbers of newly emerged species and families in the three communities were: 5 species and 2 families in the first communties, 12 species and 2 families in the second communties and 12 species and 6 families in the third communties. For the obvious effects of precipitation on annual herb and perennial herb were observed in three communities of Ceratoides latens, Sarcozygium xanthoxylon, Tetraena mongolica, the effect on shrub and half shrub was observed far small. The increase of rainfall could improve the species richness and diversity of three typical shrub communities. And rainfall increment could homogenize the structures and habitats of Tetraena mongolica and Ceratoides latens. For the three typical shrub community, precipitation had positive correlations with species number, coverage, richness index, evenness index, diversity index, and all coefficients were greater than 0.600 0. [Conclusion] Rainfall had significant impacts on species numbers, coverage, richness, evenness, diversity of the three typical shrub communities.