The invention relates to a filtering device, in particular to a water channel impurity filtering device for irrigation and drainage engineering. The technical effects that the provided water channel impurity filtering device for irrigation and drainage engineering is easy and convenient to operate, short in time and good in cleaning effect are achieved. In order to achieve the technical effects, the provided water channel impurity filtering device for irrigation and drainage engineering comprises a placement plate, a water channel, a supporting rod, a mounting plate, a transmission mechanism and the like. The supporting rod is arranged at the top of the placement plate. The mounting plate is arranged at the top of the supporting rod. The transmission mechanism is mounted on the mounting plate. A filtering mechanism is mounted on the left side of the mounting plate. A collection tank is arranged on the left side of the top of the mounting plate. Through cooperation of the transmission mechanism and the filtering mechanism, impurities in the water channel are filtered, meanwhile, by optimizing an auxiliary mechanism and a collection mechanism, the effects that operation is easy and convenient, time consumption is low and the cleaning effect is good are achieved.