Flat joint piece for wall surface composite board

The utility model discloses a wall surface composite board flush joint piece, and belongs to the technical field of wall surface composite board connecting pieces. The butt joint piece comprises a mother piece and a son piece, the mother piece is divided into a first part and a second part, the first part and the second part are respectively pasted on the side edges of the composite boards needing to be connected, one end of the son piece is buckled into the second part from the upper portion, and the other end of the son piece enters into fit connection from the opening end of the first part. Connection between the composite boards is achieved through connection of the son part and the mother part, the first part and the second part are each provided with an arc-shaped vertical plate which is concave inwards, and the arc-shaped vertical plates are matched with the wave-shaped vertical plates on the two sides of the son part to form a sealed flush joint part. The bathroom wall panel is simple in structure, ea