Abstract: The sample (10.0 mL) of environmental water was taken and polyethylene glycol-2000 (0.90 g) was added. After ultrasonic dissolution, ammonium sulphate (3.25 g) was added and the mixture was extracted ultrasonically for 10 min. After centrifugation, the upper extraction phase (50 μL) was taken and diluted to 200 μL with mobile phase. The above solution was filtered with 0.22 μm organic filter membrane. UHPLC-MS/MS was applied to the determination of residual amounts of 5 triazine herbicides in the filtrate. Zorbax Eclipse XDB-C₁₈ chromatographic column was used as stationary phase, and acetonitrile (7+3) solution was used as mobile phase. ESI⁺ and the selected ion monitoring mode were adopted in MS/MS. Linear relationships between values of peak area and mass concentration of the 5 triazine herbicides were kept in the same range of 0.100-10.00 μg·L^-1, with detection limits (3S/N) in the range of 3.72-24.3 ng·L^-1. The proposed method was applied to the analysis of samples of environmental water, giving values of recovery found by standard addition method and RSDs (n=5) of determined values in the ranges of 80.8%-115% and 0.17%-6.4% respectively.