A pet house or a pet crate is easily collapsible, foldable and portable, having four side walls, connected to a roof plate, with a frame support built to the edges of the left and right side walls, when two first zippers zip up along the left and right side walls' edges to form the complete and assembled pet crate. A special 180-degree flip of a second zipper strip is made to the portion along the edges of the roof plate, so that the orientation of the zipper teeth at the portion connected to the roof plate is reversed in direction to the portion connected to the front and back side walls, providing a stronger propping power for the corners under the roof plate, when zipped up and fully erected.