In this paper,Sophora alopecuroides,Achnatherum splendens,Artermisia ordosica and Kalidium foliatum are 4 kinds of common plant communities growing in Yanchi County of Ningxia Province.They were taken as examples to study the soil microenvironment of different plant communities in desert steppe.After the study of community composition,the basic physical and chemical properties of the soil,we measured urease,catalase,phosphatase,sucrase.The results showed that:(1)the species composition of the different plant communities were various,and the frequency of occurrences of Gramineae,Compositae,Chenopodiaceae were relatively high in survey region.(2) There were differences on soil physical and chemical properties in the 4 kinds of plant communities.For example,the soil bulk density was less in S.alopecuroides community and the total nitrogen was relatively higher,the pH and organic carbon content of soil were significantly higher than others in A.splendens community.The soil moisture content and total phosphorus were lower in A.ordosica community and the salt content was higher markedly in K.foliatum community.(3) There were differences of soil enzyme activity among 4 kinds of plant communities.The urease activity of A.splendens and A.ordosica communities topsoil soil（0-10 cm）was higher;soil catalase of A.ordosica and K.foliatum communities increased as soil deepening;soil phosphatase activity of S.alopecuroides and A.splendens communities were higher and soil phosphatase activity of K.foliatum community was no significant difference in various soil layer（P>0.01）;soil sucrase activity of 4 kinds of communities was generally low,and the little difference between the soil layer.(4) The correlation of the same soil enzyme activity was different among various plant communities.In conclusion,the different plant community characteristics and soil traits,especially the correlations of soil enzyme activities among different plant communities,can predict the succession of plant communities in desert steppe,and can be used as ways of vegetation restoration of desert steppe on the other hand.That is,moderate artificial disturb can raise soil enzyme activity,then increase biomass,which make desert steppe onto positive succession.