Provided is an angle formwork plate easy to demount. After a wall is poured and formed through combination of the angle formwork plate with a main formwork plate, a formwork can be easily demounted. The angle formwork plate comprises an angle plate, a supporting plate and a first positioning plate. The angle plate comprises a vertical plate and a joint plate, the vertical plate is provided with an auxiliary forming surface used for forming, and one end of the vertical plate perpendicularly extends towards the side away from the auxiliary forming face to form the joint plate. The supporting plate is provided with a supporting surface which is connected with one end of the main formwork plate in an abutting mode after the formwork plates are combined, and the end, away from the vertical plate, of the joint plate is connected with the supporting plate. The first positioning plate is connected with the main formwork plate in an abutting mode after the formwork plates are combined and meanwhile enables the auxiliary forming surface to be coplanar with the main forming surface of the main formwork plate. The angle formwork plate easy to demount can bear rated force to be rotated in an orientation mode, the wall and the formwork plates can be very easily demounted through the angle template plate, the construction time is greatly shortened, cost is greatly reduced, and the angle formwork plate can automatically restore.