Abstract:【Objective】Artemisia ordosica and Caragana intermedia are the two widely-distributed and efficient sand-fixing shrubs in the Hobq Desert that have received considerable attention because of the roles they may play in the vegetation restoration. Soil bacteria diversity is an important indicator of the state of soil microbial communities and one indicating progress of ecological restoration.This project is oriented to study changes in community structure and diversity of soil bacteria in the process of vegetation and ecological restoration in the Hobq Desert relative to type of vegetation. 【Method】In this study, two types of vegetations, naturally restored Artemisia ordosica and artificially planted Caragana intermedia, were chosen for comparison to see effects of the vegetations on community structure and diversity of soil bacteria with a tract of moving sand land as control. The sample plots were set up in 1995 and soil samples were collected from the rhizospheres of A. ordosica and C. intermedia and bulk soil in the 0~20 cm soil layer and CK in August 2014 for analysis of soil bacteria diversity using the high throughput sequencing method. And relationship between soil bacterial diversity and soil physic-chemical properties, and the effect of soil physical and chemical properties on distribution of bacterial community were also studied through canonical correlation analysis and Cononical correspondence analysis.【Result】(1) Chao1 index, shannon index and ACE index are important indicators of soil bacterial diversity and richness. In terms of Chao1 index and shannon index, the sample plots displayed an order of rhizosphere soil of A. ordosica > rhizosphere soil of C. intermedia > non-rhizosphere soil of A. ordosica > non-rhizosphere soil of C. intermedia > soil of CK, while in terms of ACE index, they followed another order: rhizosphere soil of A. ordosica > rhizosphere soil of C. intermedia > non-rhizosphere soil of C. intermedia > non-rhizosphere soil of A. ordosica > soil of CK.(2) Classification at the phylum level shows the bacterial communities in the samples were mainly composed of Proteobacteria, Acidobacteria, Actinobacteria, Bacteroidetes, Gemmatimonadetes, Planctomycetes, Verrucomicrobia, Firmicutes and Chloroflexi, accounting for 88.67%~94.19%. Proteobacteria, Acidobacteria and Actinobacteria were the dominant bacterial groups in the samples, and Proteobacteria was the highest in abundance. The four subbgroups under Proteobacteria followed a similar trend in variation. Relative abundance of α-proteobacteria in the rhizosphere and bulk soils under either vegetation exhibited a sharply rising trend, increasing in the rhizosphere of A. ordosica and C. intermedia increased by 106.46% and 70.60% respectively. (3) Soil organic matter, total N, total K, readily available N, readily available K, and soil water are the main soil factors affecting abundance and diversity of soil bacteria communities. Correlation analysis of soil physic-chemical properties with relative abundance of dominant soil bacteria groups shows that the abundance of Proteobacteria was significantly related to soil organic matter, total N, readily available N, readily available P, and readily available K, while the abundance of Acidobacteria was to soil organic matter, total N, readily available N, readily available P and readily available K. Intrestingly, the abundance of Actinobacteria was not so much related to soil factors. Cononical correspondence analysis indicates that soil organic matter, total N, total K, readily available K and readily available N play an important role in triggering variation of genetic diversity of the bacterial communities in the soils. 【Conclusion】Results show that compared to moving sand land, the two tracts of lands with vegetation restored have demonstrated positive effects on community structure and diversity of soil bacteria, whose abundance, diversity and evenness have been significantlt improved. Between the two types of vegetation restoration, the naturally restored A. ordosica vegetation was higher than the artificially plated C. intermedia vegetation in effect increasing abundance of soil bacterial community. Bacterial community in the untreated soil is quite simple in structure. The restoration of vegetation enriches soil microbial groups, making the community of soil bacteria diversified in the rhizosphere and non-rhizosphere soils. Relative abundance of a-proteobacteria under the vegetation of A. ordosica and C. intermedia significantly increased, especially under the vegetation of A. ordosica.