Photodegradation of flucythrinate ((RS) α‐cyano‐3‐phenoxybenzyl (S)‐2‐(4‐difluoromethoxy phenyl)‐3‐methyl butyrate) in water and on soil surface was studied. On exposure to natural sunlight flucythrinate was photodegraded with half lives of 3.8d in distilled water, 1.0d in tap water and 0.5d in 2% aqueous acetone. Flucythrinate applied on soil thin layer plates was promptly dissipated from four kinds of soil by photodegradation with a half life of less than 2d. The photoreaction involved were cleavage of ester, oxidation of CHO group to COOH, hydration of CN to amide and hydrolysis of amide to COOH group.