Abstract: In order to study the photochemical degradation law and the environmental impact of amicarbazone, the author used the method of HLPC- UV, studied the photolysis dynamics of amicarbazone in different environmental water, different pH, different surfactants, different humic acids through laboratory simulation experiments. The results showed that the photolysis of amicarbazone was faster in alkaline solution than in neutral condition, and the half-lives were 2.9 h and 6.4 h. The photolysis was the slowest in acidic condition and the half-live was 7.6 h. The photolysis rates in 4 different types of water were : river water＞field water＞ lake water＞distilled water. The photolysis half-lives in different concentrations of humic acid were 1.3, 3.5 and 5.8 h. In the experiment of different types of surfactant, the photolysis rates were: Span 60＞SDBS＞ Tween 80, and the half-lives were 2.1, 2.5, 10.2 h, respectively. The amicarbazone was not stable in alkaline and neutral conditions, and it had a fast photolysis in river water. Low concentration humic acid could accelerate photolysis process of amicarbazone. Amicarbazone was not stable in Span 60.