Minqin County is one of the major areas of desertification in China.In this paper,the stability and ecological effects of 5 mainly plant communities were analyzed with 12 years of positioning observations in Minqin desert area.Observations show:Vegetation cover was significantly decreased of Artemisia arenaria and Ephedra przewalskii,and projective cover is significantly decreased of A.arenaria and Haloxylon ammodendron plantation.Vegetation cover of Nitraria tangutorum also decreased.The analysis showed that:(1)Plant community of cover relatively low stability is strong.The plant community of cover relatively high stability is weaker.(2)Year rainfall is the key factor for determining the vegetation cover and the projector cover.(3)Ecological functions of Nitraria tangutorum per unit area is the largest,followed by E.przewalskii,and the third is N.tangutorum+H.ammodendron.Ecological functions of A.arenaria per unit area is the lowest.Vegetation of desert area sparse and plant shoots distribution is extremely irregular.Vegetation cover is calculated with plants crown does not reflect the actual situation of surface covered by vegetation.