Abstract: As one of the major groups of plant growth-promoting bacteria,phosphate-solubilizing bacteria play an important role in the development of green agriculture and control of desertification.The present research mainly focus on phosphate- solubilizing bacteria of farmland,classic grassland and desert ecosystem,however plant growth-promoting rhizobacteria of desert steppe has rarely been studied.The phosphate-soiubilizing bacteria were isolated by the insoluble phosphate medium, and the phosphate-solubilizing ability of the isolates were detected by the potassium persulfate digestion and Mo-Sb anti colorimetric method.42 phosphate-solubilizing bacteria were isolated from the rhizosphere of four dominant plants in desert steppe of Siziwang Banner.The 42 strains were classified into 5 groups and 19 genuses.Among them,19 isolates （45.2%） belong to the Actinobacteria,5 strains （11.9%） belong to the Bacilli,16 strains （38.1%） belong to α-proteobacteria,1 strain （2.4%） belong to β- proteobacteria,and 1 strain （2.4%） belong to γ-proteobacteria.The results showed that strain GP0501,GP0506,GP0507 and GP0509 have the strongest phosphate solubilizing ability,the phosphate solubilization capacity was 77.57,65.89,58.08,68.02g/μ mL,respectively.The 4 strains have great potential of application,which all belong to Bacillus.