A prefabricate liner plate of modified asphalt concrete comprises a lower asphalt concrete layer, a reinforced layer and an upper asphalt concrete layer. The section length of the liner plate equals to the section arc length of the channel prefabricate groove. The section thickness of the liner plate approximates to the prefabricate groove thickness. The liner plate is 1-3 meters in width. The reinforced layer is composed of fiberglass gridding or polyester gridding or wire gridding. This prefabricate liner plate of modified asphalt concrete is applied to irrigation channels for the first time in China, thus solves the problems of difficulty and high cost in adopting mechanized equipments on site, in particular the difficult problem of constructing medium-small channels.