A strain of FLDA capable of degrading metsulfuron-methyl aerobically was isolated from sludge collected from a pesticide (metsulfuron-methyl) plant.Based on analysis of its 16S rDNA,morphology,physiological and biochemical characteristics,strain FLDA was identified preliminarily as Pseudomonas sp.This strain of bactera could degrade 72.6% of 30mgL^-1 metsulfuron-methyl in liquid medium within 5days.The optimal pH and temperature for metsulfuron-methyl degradation was 7.0 and 30℃,respectively.The degradation rate was related positively to initial inoculation rate.Enzyme distribution experiment showed that the metsulfuron 2 methyl degradeing enzyme in the bacterium was endoenzyme.Strain FLDA could be used to degrade metsulfuron-methyl in soil.