A dichloromethane-degrading bacterium Methylobacterium rhodesianum H13 which utilized the DCM as the sole carbon and energy source was isolated. According to the research, M. rhodesianum H13 could completely degrade 5 mmol x L(-1) DCM in 23 h with the initial cell concentration of 0.82 mg x L(-1), pH 7.0, 30 degrees C, and the cell yield rate was about 0.136 g x g(-1) DCM. With the degradation of DCM, Cl- concentration gradually raised (the release of Cl- concentration was about 2 times higher as the DCM), pH value dropped to 6.75, and the solution was weakly acidic. Temperature, pH, DCM concentration, Cl- concentration and other factors were investigated through the shake flask experiments, and the optimal conditions for DCM degradation were: temperature 30 degrees C, pH 7.0. The study also indicated that 5 mmol x L(-1) of DCM was the optimum concentration for M. rhodesianum H13 and high levels of DCM could inhibit the degradation. The research has an important application value for the DCM environmental pollution.