A technology of wastewater treatmentcompound artificial wetland was developed in connection with the characteristics of water pollution in small cities and towns in China. That compound system was composed of vertical baffled wetland filter under anaerobic conditions and lateral subsurface flow wetland bed under facultative conditions. By setting up the inner backflow system, the nature reoxygenation area and the gravel filler with a particle size of 8~30 mm, the dissolved oxygen(DO) division in the system was achieved with the optimization of the flow pattern and the increase of treatment efficiency. The application results indicated that, under the conditions that the water flow rate was 300～450 m3/d, COD, NH+4N and TP concentration of the inffluent were 60~250 mg/L, 4.5~23 mg/L and 1.5~8 mg/L respectively. And these values of the effluent were 20~30 mg/L, 2~4 mg/L and 0.3~0.5 mg/L respectively at low temperature and could fall below 30 mg/L, 4 mg/L and 0.43 mg/L at normal temperature.