In order to clarify the synergistic effect of Paenibacillus mucilaginosus and Rhizobium meliloti on the reclamation of dumping in mining area, the soil of dumping in the mining area was used as the substrate for a pot experiment, and the single inoculation treatments of two bacteria, dual inoculation treatments and control were set up. The dosages of P. mucilaginosus and R. meliloti in treatments were 1.50% and 0.25%, respectively. The alfalfa yield, leaf physiological indexes, soil available nutrients contents, soil microbial indexes were determined. The results showed that inoculant of P. mucilaginosus and/or R. meliloti could improve the yield of alfalfa, and dual inoculation treatment was the highest and better than the control by 110.27% and 124.32% for biomass and nodules index, respectively. As for physiological indexes, the effect of dual inoculation treatment was lower than that of single inoculation treatments, and no synergistic effect was found. In terms of soil nutrients and microbial properties, single inoculation of P. mucilaginosus only significantly increased the soil available potassium content, and single inoculation of R. meliloti had a significant effect on most indicators. Dual inoculation treatment had the best effect. It increased significantly the contents of available nitrogen and potassium of soil by 94.14% and 84.55% respectively compared with the control. The soil microbial indexes, including MBC content, respiration intensity, invertase, urease, phosphatase, and catalase activities, were significantly increased by 204.02%, 65.86%, 212.32%, 91.87%, 30.57% and 51.87%, respectively. The dual inoculation treatment showed a significant synergistic effect on the alfalfa yield, soil nutrient and microbial indexes. Therefore, the dual inoculant of P. mucilaginosus at the dosage of 1.50% and R. meliloti at the dosage of 0.25% could effectively improve the soil reclamation effect of the dumping with a synergistic effect and could be used as an efficient method for the reclamation of the dumping in the mining area.