Abstract: Metal packer uses super- elasticity NiTi metal alloy, instead of rubber, as seal. At specific temperature, it enlarges and sets down when a pressure is applied, and it automatically withdraws when the pressure is removed, thus unsetting can be realized Metal packer has several advantages such as its inner drift diameter being larger than conventional packers, being corrosion resisting and having a long service life. Laboratory testing achieves a seal pressurization of 35 MPa, a hanging force of 200 kN and an unsetting force of 180 kN.