In order to improve the safety of the tubular column in offshore "three high" gas wells and ensure the good working performance of the kava,the HPC070401 packer bi-directional cartridge kava was used as an example.The mechanical behavior of kava biting process was studied by combining the slip line theory method,numerical simulation and experimental method,the contact stress distribution law between kava and casing,the depth of kava teeth biting into casing and fatigue life were analyzed,and the sufficient and necessary criterion of reliable work of packer kava system was established.The results of the study show that:the sitting card pressure increases,the depth of kava teeth biting into casing also increases,with the sitting card pressure of 35 MPa,42 MPa,48 MPa,55 MPa,the depth of kava biting into casing is 0.259 93 mm,0.294 25 mm,0.323 53 mm,0.365 61 mm.The sitting card pressure increases,the localized plastic deformation of the kava tooth tip increases,with the sitting card pressure of 35 MPa,42 MPa,48 MPa,55 MPa,under the symmetric cycle fluctuation of 20%,the number of fatigue life cycle of the kava is 951 110,789 540,717 160 and 629 260.Through the high temperature and high pressure packer kava anchoring experiment,the measured depth of kava biting into casing is between 0.350 mm and 1 mm,which is in good agreement with the finite element simulation results.Combined with the evaluation criterion and the fatigue experiment of high temperature and high pressure packer,the stress relaxation coefficient of casing caused by fatigue cumulative damage is 0.18.