To develop a water quality purification system proper for agricultural water a stair-type Up and Down Flow Constructed Wetland system was installed. When average influent concentrations of SS, BOD, T-N, T-P were 59.7mg/L, 6.6mg/L, 1.98mg/L and 0.09mg/L, the effluent were 1.3mg/L, 0.6mg/L, 1.10mg/L and 0.10mg/L, respectively. Therefore, average removal efficiencies of SS, BOD T-N and T-P in this process were 97.8%, 90.9%, 47.7% and 0%, respectively. The result showed that this system is a feasible alternative for agricultural water quality purification.