Serial drop water composite wetland system for treating non-point pollution

The invention provides a serial drop water composite wetland system for treating the non-point pollution. The system is composed of a cuboid package, a wetland device, a wetland substrate and wetland plants; two same flow lines, namely a room temperature flow line 1 and a low temperature flow line 2 are connected in parallel to form the system; each flow line is composed of six cells and one water-collecting tank; and the wetland substrate has four layers, wherein the first layer, namely the topmost layer is a clay layer, the second layer is a fine sand layer, the third layer is the mixed layer of coal cinder and limestone and the fourth layer is a cobble layer. The device has the function of efficiently purifying sewage.