The pressure -test plug is a specialized tool used in testing the pressure of casing string and blowout preventer stack in drilling or field.When the oil,air or water well in which the casing has been run and wellhead equipment has been installed works for primary laying pressure tesitng for casing and blowout preventer stack ,adoption of this tool shall be easy and reliable.The leather cup of plug is made of special super rubber materials,the sealing working pressure is up to 75Mpa.