[Objective] To better understand how precipitation influences plant growth in Minqin County, Gansu Province.[Methods] Line transect method and grid stabbing method were used to monitor vegetation change under three site conditions in Minqin County. It was monitored four times during ten years. The investigation data were analyzed by Excel software.[Results] Interannual and annual meteoric water changed greatly, which was harmful to plant growth. Some plant growth depended mainly on precipitation in sandy desert grassland of Xishawo and gravel desert grassland of Hongguozijing in Minqin County, and hence plant growth hasd a close relationship with precipitation, especially the annual herb. The other plant depended mainly on groundwater in salinization desert grassland of Baituing where groundwater level was higher. It was harmful to plant growth that the salinity accumulated on surface soil was leached into root zone by precipitation.[Conclusion] The plant growth depends on precipitation or groundwater and is influenced by precipitation greatly. The desert vegetation declines gradually and also desertification is aggravated increa-singly in Minqin County.