Abstract: Problems and difficulties of sand washing in horizontal well are analyzed,and the technical feature and tool con struction are introduced,including the structures and princi-ples of the manufactured dual-channel sand washer,sand washing blowout preventer and rotation injection sand wash-ing point,so a suit of technology sand washing in horizontal well is presented,and the corresponding techniques can be selected in accordance with the sand production in oil produc-er.The field results show that this technology of sand wash-ing can meet the requirement of sand washing in horizontal well.