Two phosphate solubilizing bacterial strains,PSB-1 and HZP1,were isolated form soybean nodules and rhizosphere soil. The ability of these two strains to produce IAA (indole-3-acetic acid IAA) and the ability to dissolve inorganic phosphorus were measured by Salkowski colorimetry and molybdenum antimony-phosphonium colorimetry. Soybean and Astragalus sinensis were co-inoculated. Results showed that both two phosphate solubilizing strain produced IAA. The legume growth-promoting effects of the phosphate solubilizing strains and rhizobium inoculum were investigated in unsterilized soil and soybean planting field. Inoculation with HZP1 or PSB-1 promoted the growth of Astragalus sinensis and soybean. Co-inoculation of phosphorus-solubilizing strains with rhizobium further increased the shoot biomass,fresh weight of nodules and the number of nodules of soybean and Astragalus sinensis. The results of field tests showed that inoculation with rhizobium or phosphate dissolving agents alone had a certain effect of increasing yield but double inoculation with rhizobium and phosphate dissolving bacteria did not increase the yield significantly.