To investigate the effect of microbes on oil degradation, we use the method of introducing selected bacteria to the soil samples. Experiment shows that the combined bacteria are preferable to the single ones because of their synergetic functions. The optimum condition for oil degradation was controlled at pH 8.0, 25 degrees C. Some surfactants are helpful to breed bacteria, thus improves the oil degradation. After adding TW-80 (300 mg x kg(-1)) for 8 days, the number of bacteria was amplified 6.22 times and the oil degradation rate was enlarged 20.1%. Adequate amount of H2O2 is beneficial for microbes to decompose oil, but its overdose may slay bacteria. 400 mg x L(-1) H2O2 each time is suitable dose. In 11 days after 7 000 mg x L(-1) H2O2 was added entirely, the oil degradation rate rose greatly from 39.81% (without H2O2) up to 66.79%.