Through the potted experiments of tomato in greenhouse, the biocontrol ability of 9 strains of rhizobacteria to root knot nematodes(Meloidogyne incognita) was studied. The results showed that these strains could reduce the formation of the galls: the control efficiency of strain 119 was the greatest at 57.75% after 30 days, and 55.88% after 60 day. These 9 strains could also promote the growth of tomato plants too: strain 333 showed best growth promotion ability, the plant height and mass were 43.00 cm and 11.17 g respectively, and were increased by 37.25% and 76.46% compared to those of CK. However, the application of a mixture of the strains did not provide significant disease suppression compared to the application of a single strain, but could significantly promote the growth of tomato plants. Strain 119 was classified as Bacillus megaterium,based on the analysis of their 16S rDNA sequences, and the morphological and biochemical tests.