The invention discloses an outdoor portable foldable disposable water cup, which is composed of a right cup wall, a left cup wall, an inner fold mark and an outer fold mark. The right cup wall and theleft cup wall are connected with each other through an inner fold mark and an outer fold mark, and the inner fold mark and the outer fold mark are connected with each other in a zigzag manner at thebottom of the water cup. The water cup can be telescoped like a spring when being transported and stored. The storage space is saved. The transportation is convenient, and the water cup which is veryflat in contraction can also be vacuum packed, so that the cleaning inside of the water cup can be ensured to the maximum extent.