In order to reduce the failure accident of conventional compression packer, uniaxial tension and compression tests of rubber materials of packer were carried out, and the mechanical properties of conventional compression packer was analyzed based on the test data and Abaqus large deformation contact finite element analysis.A sealing structure of expandable packer was designed.The effects of different pressure difference, temperature and friction coefficient on the sealing performance of expandable rubber cylinder were analyzed. Finally, the designed expansion rubber cylinder was experimentally studied. The results show that in the process of completing the sealing of the rubber cylinder of the conventional packer, the upper rubber cylinder mainly plays the role of sealing, and the stress is large;excessive stress will cause fatigue failure due to the compression of the shoulder of the conventional rubber cylinder;the expansion sealing method can improve the sealing performance of the rubber cylinder and reduce the compression deformation failure of the shoulder of the rubber cylinder.It is found that the setting and pressure bearing performance of the new sealant cylinder is stable in the temperature range of 108 ℃ to 140 ℃.