Abstract: The residual dynamics and leaching dynamics of atrazine in corn field were studied by HPLC. Results showed that the half-life in soil for atrazine 40% FL applied alone at the rates of 2.25 kg/hm2 (a.i)., 4.50 kg/hm2 (a.i) were 19.1 days and 18.1 days, respectively. Field experiments revealed that disappearance rate of atrazine in soil followed the first-order rate law. Over the 120-day growing season of the corn, the degradation and leaching of the residual atrazine in the surface of soil were found. And most of the atrazine applied was kept in the top of the soil. The leaching experiment results showed that the leaching depth was more than 30 cm in feild. The rate of atrazine applicated could influence the leaching behavior of atrazine in soil profile. Initial detection of atrazine was occurred in the depth of 25~30 cm at 27 days after high rate application but no atrazine was found in the lower rate treated soil. As the atrazine application rate was decreased, atrazine eluted through the soil profile over a longer period of time. It suggested that atrazine has low potential to reach the groundwater. The main factors affected the leaching are application rates and the characters of soil.