A drainage ditch filtering device is characterized by comprising a frame and a filtering net; the filtering net is semispherical; the edge position of the filtering net is fixed on the inner side of the frame; bugles are further arranged on two sides of the periphery of the frame; and the drainage ditch filtering device also comprises grooves which correspond to the bulges and are fixed on the ditch walls of the two sides of the drainage ditch. The convex length of the bugles is 2 to 5 cm. The has the following beneficial effects: the drainage ditch filtering device can be mounted in the drainage ditch, can filter discharged wastewater, has a good filtering effect, prevents natural water from being polluted, and is easy to mount and easy to change.