A strain of becteria with strong ability to degrade phenol were isolated from the activated sludge sewage disposal workroom in Baotou.Through increasing the phenol concentration of the culture medium to domesticate the strain step by step,a strain was isolated which can biodegrade the phenol effectively.And the test result shows that the strain is Pseudomonas sp that can use phenol as the only carbon source as shown by the control experiments.The strain′s optimum temperature is 30 ℃ and its optimum pH is 7.0.Being the aerobic bacteria,it enhances the degradation capability with enough air,so further research on the strain action may play an important role in the protection of the environment.