Abstract: Prochloraz and its metabolites,2,4,6-trichlorophenol,were determined by liquid chromatography-electrospary ionization mass spectrometry (LC-ESI-MS) and gas chromatography,respectively,to explore the degradation mechanism of prochloraz in mushroom and the cultivated soil.Field residue decline of prochloraz in mushroom and soil was found to conform to exponential equation.The half-life of prochloraz was 3.5 days in mushroom and 20.3 days in the soil.The amount of 2,4,6-trichlorophenol in mushroom increased at first,reached maximum at the third day and decreased after that,whereas the metabolite in the soil kept increasing all the while up to 45 days.