A pouch air valve includes a hollow tube, a first suction plate, a second suction plate and an air valve. The hollow tube has a central passage running through two sides thereof. The air valve fills and seals the central passage. The first and second suction plates encircle the outer wall of the hollow tube and suck the sealed pouch respectively to couple each other. A method for using includes the following steps: preparing a pliable sealed pouch and forming on the sealed pouch an aperture smaller than suction areas of the first and second suction plates; running the hollow tube through the aperture and positioning the first and second suction plates at two sides of the sealed pouch to couple each other. Air can be sucked out from the sealed pouch for vacuuming or fresh-keeping gas can be injected into the sealed pouch to meet requirements.