The invention discloses a filter screen device. The filter screen device comprises a support, winding wheels, a conveying belt and a filter screen. The support comprises two side plates and a cross rod. The two side plates are arranged basically in parallel, and the cross rod is fixedly connected with the two side plates. The winding wheels are arranged on the two side plates correspondingly. The conveying belt can be stretched and wound on the winding wheels. The filter screen is fixed to the conveying belt in a stretching mode so as to cover the support. The filter screen device is matched with a dust suction device of a wall-mounted type air conditioner, and the filter screen can be moved by rotating the winding wheels so that dust on different positions of the filter screen can be removed through the dust suction device.