An easy-tear sticker and a protective film assembly are provided. The easy-tear sticker includes: a main body layer and a first adhesive layer, the main body layer includes an attaching part and a tearing part, and the first adhesive layer is disposed on the attaching part, the attaching part includes a first attaching area and a second attaching area, a shape of the first attaching area is a right-angle triangle, and a shape of the second attaching area is a strip; the tearing part is connected to the attaching part by a first right-angle side of the right-angle triangle, and the tearing part is configured to be folded toward the attaching part along the first right-angle side, so as to cover a surface of the attaching part facing away from the first adhesive layer.