根据广东省台山市都斛镇灌排河网的特点 ,建立了河网非恒定出流数学模型。该模型根据潮水位的变化 ,模拟河网的水位和流量变化过程。通过调节挡潮闸的运行时间和开启度 ,使该系统既能满足排涝要求 ,又能合理控制河网水位 ,使之满足农作物生长对地下水位的要求 According to the characteristics of irrigation and drainage network in Du Town, Taishan City, Guangdong Province, a mathematical model of unsteady outflow of the river network was established. The model simulates the change of water level and flow in the river network according to the change of tidal level. By adjusting the running time and opening degree of the tidal barrier, the system can not only meet the requirements of drainage but also rationally control the water level in the river network so as to meet the requirement of the crop growth for the groundwater level