Abstract: Analysis of community composition in the process of desertification in Shenmu county, Shanxi Province,shows that. (1)The proportion of hemicry-ptophytes decreases obviously. (2)The minimum area decreases from 45m² to 2. 25m². (3)Coverage-desertification stage curve roughly likes a "s". The coverage of climax association is not the largest one in the desertification series. (4)The Simpson index of species decreases while its eveness and dominance increase in the development process of desertification. (5)The dominance-diversity curves of no desertification stage and initial desertification stage are roughtly of log-normal distribution. The curves apporache to a geometric progression distribution at the latest stage.