In order to reveal the response mechanism of plant diversity restoration to soil habitat after fencing in desert steppe, the plant communities in sierozem soil and aeolian sandy soil habitats of fenced and moderately grazed grassland were selected as the research objects. The variance analysis and redundancy analysis (RDA)were used to study the changes of plant diversity after enclosure and its relationship with physical and chemical factors of soil habitat. The results showed that:(1) compared with moderate grazing, enclosure significantly reduced plant diversity in sierozem soil and aeolian sandy soil. With the increase of enclosure years, plant diversity was significant, and the negative effect of enclosure increased with the increase of enclosure years. (2) There was a negative correlation between plant diversity and biomass in both soil habitats. The differences of plant communities between sierozem soil and aeolian sandy soil were as follows:(1) In sierozem soil, plant diversity was positively correlated with sand, while biomass was positively correlated with organic carbon and total nitrogen. (2) In aeolian sandy soil, plant diversity was positively correlated with organic carbon and total nitrogen, as well as biomass was positively correlated with electrical conductivity. In conclusion, the effects of different soil habitat types should be fully considered in the restoration of plant diversity of the degraded grassland in desert steppe in the future.