Abstract: In order to obtain highly efficient dissolve phosphorus Rhizobium meliloti strain with two antibiotic-resistant, a dissolve phosphorus rhizobium strain L-5 was irradiated by microwave. The microwave mutagenesis parameters were optimized, and the genetic stability, phosphate solubilizing power and antibiotic resistance of the mutant were investigated. Five highly efficient dissolve phosphorus strains with two antibiotic-resistant named LW59, LW81, LW104, LW107 and LW135 were obtained through the microwave irradiation (600 W, 30 s). In several passages, a mutant named LW107 with steady phosphorus solubilizing capability was obtained and it exhibits resistance to 300 mg/L ampicillin and 100 mg/L kanamycin. The phosphate solubilizing power reaching 16.67 mg/L (14 d) and nitrogenase activity are 112.59% and 11.7% higher than those of initial strains, respectively. Two strains of the LW107 and L-5 are inoculated onto the live plants and it is testified that nodulation ability of them is with no significant differences(P＞0.05).