Abstract: In order to study the chemical behavior of flumioxazin. The photolytic and hydrolytic properties of flumioxazin under different conditions were investigated using the indoor simulation test method. The results showed that the hydrolysis half-life of flumioxazin was 63.00, 33.00 and 28.50 h in the buffer solutions with the initial concentration of 2 mg/L at pH, 5, 7 and 9, respectively. The degradation was much faster in alkaline solutions than in the neutral and acidic solutions. The hydrolysis half-lives of flumioxazin was 33.00, 23.10 and 8.88 h in the buffer solutions with the initial concentration of 2 mg/L at pH 7, 15, 25 and 35℃. The higher the temperature, the faster the hydrolysis rate. The hydrolysis rate of fulmioxazin in river water was higher than that in tap water and distilled water. Under the irradiation of 300 W mercury lamp, the photolysis rate of flumioxazin was higher than that under the acidic and neutral conditions. The photolytic rates of flumioxazin in different organic solvents showed the following sequence:methanol> ethyl acetate> N-hexane> acetonitrile> acetone. The photolysis rate under different light sources followed the sequence:500 W mercury lamp> 300 W mercury lamp> xenon lamp. The results provided a scientific basic for environmental risk assessment of flumioxazin.