A bacterium(designated as LW-3), capable of degrading Chlorimuron-ethyl, was isolated from the long-term contaminated soil by Chlorimuron-ethyl. Based on physiological and biochemical analyses and sequences comparison of 16S rDNA, strain LW-3 was identified as Pseudomonas sp. LW-3 could use Chlorimuron-ethyl as sole nitrogen source for growth. The optimum pH and temperature for degradation of Chlorimuron-ethyl were pH 6.5~7.2 and 30°C~35°C, at same temperature the pH change to the Chlorimuron -ethyl degrading influence is large. When the pH and temperature were pH 6.5 and 32°C, 50 mg/L Chlorimuron-ethyl could be degraded to 70%~80% level within 7 days.