Abstract: A method had been developed to determine flubendiamide (NNI-0001) and its metabolite (NNI-des)residues in soil and water.The samples were extracted by acetonitrile,followed by clean-up on PSA cartridge and analyzed by UPLC-MS/MS.The limit of detection of flubendiamide and its metabolite in soil and water were 0.002 mg/kg and 0.001 mg/L,respectively.The limit of detection was 1.2×10-13 g for flubendiamide and 3.1×10-14 g for NNI-des.External reference method was used for quantitative determination.When the concentration of flubendiamide and its metabolite NNI-des was quantitative from 0.001 to 1 mg/kg(mg/L),the average recoveries varied from 78.2% to 108.2% with the coefficient of variation of 8.2%-15.3%,respectively.The study indicated that the half-life of flubendiamide in soil and water was 1.0 days and 5.4 days.The rate of decline exceeded 85% 21 days after application.Flubendiamide belongs to the easily degradable pesticide.