Trifloxystrobin{methyl-α-(methoxyimino)-2-[({1-[3-(trifluoromethyl)phenyl]ethylidene}amino)oxymethyl]benzene-acetate} (TFS) is a systemic broad-spectrum foliar fungicide marketed by Bayer Crop Science. TFS exhibits activity against many fungal pathogens such as Ascomcete, Basidiomycete, Deuteromycete and Oomycete classes. It has particular effect on anthracnose 1 , downy mildew, powdery mildew 2 , rice blast 3 , rice shealth blight and false smut 4 attacking vegetable, fruit and grain crops. The compound can be used to control fungus in greenhouse, nursery, orchard, vegetable and paddy field crops. Although trifloxystrobin is considered to be less toxic to birds, mammals, bees, other beneficial insects and earthworms 5 , it has been classified as highly toxic to Bufo cognatus tadpoles 6 , Oncorhynchus mykiss trout and the marine crustacean Mysidopsis bahia 5. Hence, aquatic organisms may be at risk of exposure to trifloxystrobin through spray drift, direct overspray, atmospheric transport, runoff and movement of animals through fields during application. Therefore, it was necessary to assess the degradation of trifloxystrobin in aqueous solution. The primary degradation in aquatic systems is hydrolysis and photodegradation. Trifloxystrobin is the first strobilurin compound with an oximether side chain. As shown in Fig. 1, the chemical structure of trifloxystrobin can appear in four