A gas-cycle incubation system (H₂ treatment system) and mineral salt agar medium was used to isolate and culture hydrogen-oxidizing bacteria in Medicago sativa rhizosphere, and 37 strains were finally isolated and cultured, 8 strains of which could absorb H₂ more than 2.44×10^-4 mol/L was identified as Pseudomonas sp., Plesiomonas sp., Pimelobacter sp., Xanthobacter sp., Leminorella sp., Terrabacter sp., Rarobacte sp. according to the cell, colony form and biochemical characteristics. The heterotrophy culture condition of strain WMQ-7 was also studied. The enzyme activity of strain WMQ-7 was 0.671 U/µg and the content of siderophore produced by strain WMQ-7 was 7.1996 µg/mL. 16S rDNA sequence of strain WMQ-7, FMG-3, FMG-5 was analyzed and built the phylogenic tree. From the physiology characteristic and inherited characteristic, strain WMQ-7 was finally identified as Pseudomonas putida (GenBank accession number EU807744). Stain FMG-5 was 94 % similar to the Rhizobium etli, while the 16S rDNA sequence of strain FMG-3 could not find a similar comparison in GenBank. In the experiments of the 8 hydrogen-oxidizing bacteria effect on wheat, the results showed that strain WMQ-7, FMG-3 and FMG-5 had strong ability to promote the growth of wheat. It is possible that the plant growth promoting mechanism of strain WMQ-7 was due to its ACC deaminase activity and the siderophore.