Photolytical kinetics of vinclozolin in 4 kinds of organic solvents were observed in this paper. Under high-pressure mercury lamp,half-life of vinclozolin in methanol,acetonitrile,hexane and acetone,was 27.51 min,46.52 min,1.32 h and 46.52 h,respectively,and 0.70 h in acetone,14.17 h in methanol,24.58 h in hexane under sunlight,but vinclozolin photolized in acetonitrile was very slowly.The results indicated that organic solvent as reaction matrix affected significantly photodegradation of vinclozolin,i.e.,there was a competitive effect on absorbing light between solvent as reaction matrix and vinclozolin as solute.