Abstract: In order to promote the development and application of plant growth promoting rhizobacteria, promoting rhizobacteria of maize was isolated, and the bacteria of maize（Mitsuaria sp. YM0137） was based on the colonization of strain YM0137 in maize roots. The effect of strain YM0137 on maize yield was determined. The strains were purified by local gradient solution dilution technique, select bacteria to promote maize growth, determine the classification status of strain YM0137 by 16S rRNA gene sequence analysis and physiological and biochemical reaction, determine the colonization of strain YM0137 by colony measurement and SEM, detect the growth curve of strain YM0137, and apply the fertilizer YM0137 in the field. For strain YM0137, compared with the control, the plant height of maize seedlings treated with strain YM0137 was increased by 18.5%; After the phylogenetic and physiological and biochemical analysis, strain YM0137 was a chitosanase-producing bacterium（Mitsuaria sp.）; Strain YM0137 could colonize on the maize root surface by the produced microcolonies, and the colonization quantity in the maize root surface showed a gradually increasing trend; At the same time, an endogenous plasmid was found in the strain YM0137; The yield test results showed that there was no significant difference between bacterial fertilizer YM0137 replacing 25% chemical fertilizer and conventional fertilizer in maize yield, but compared with no chemical fertilizer, it could significantly increase maize yield, reduce chemical fertilizer application.