9 strains Rhizobia were isolated from different Acacias crassicarpa growing different stands, and Acacia crassicrapa seedlings were inoculated with those Rhizobia. Six months later, the growth of seedlings and the N, P, K concentration of soil were tested. The results showed that the height growth and total biomass of inoculating with rhizobia were increased 0.89-40.18%,52.33-147.67% of control, all the seedlings were nodulated after inoculating with R1, R5, R7, R8 Rhizobia strains;the nodule biomass of inoculation were 1.636-5.20 times higher than that of the control. On the other hand, the N, P, K concentration of soil has greatly increased after inoculating with the rhizobium. In view of the height, and total biomass of plant, the N, P, K concentration of soil, etc., the strain R6 and R7 were the better.