Economic wetland system for ottelia acuminata macrobenthos for purifying agricultural runoff

The invention provides an economic wetland system for ottelia acuminata-macrobenthos for processing agricultural runoff. The economic wetland system comprises a pesticide removal tank and a wetland unit, wherein the pesticide removal tank is connected with a water outlet of an intake tank; straws are filled into a tank body of the pesticide removal tank; the wetland unit is connected with the water outlet of the pesticide removal tank; a clay waterproof layer, a substrate layer and a flooding layer are sequentially arranged on the bottom of the wetland unit from bottom to top; ottelia acuminata is planted on the substrate layer; spiral shells and the like are also fed to the wetland unit. The pesticides of the wetland unit are removed by the pesticide removal tank with the straws, and a carbon source is provided, so that microorganisms, the ottelia acuminata and the spiral shells in the wetland unit can form a good ecological cycle system. Thus, the wetland system can stably run for a long period of time. The ottelia acuminata and the spiral shells in the wetland unit have relatively high economic value, and the economic performance of the wetland can be further improved.