The conditions of high temperature, high pressure and high sulfur content in deep well oil and gas exploitation put forward higher requirements for the sealing ability and service life of the downhole packer. K344 steel belt packer can improve the pressure bearing capacity of the expansion rubber cylinder and the stress condition in the process of pressure bearing and service life through the laminated steel belt between the inner and outer rubber cylinders, which is suitable for the requirements of deep well oil and gas exploitation. In this paper, the finite element software was used to simulate the setting process, the contact stress distribution law of the key components (inner rubber cylinder, outer rubber cylinder and laminated steel strip) and the mechanism of laminated steel strip to prevent the rubber cylinder from "shoulder protruding" were obtained. The optimal distance between the laminated steel strips at both ends and the optimal radius of the hoop fillet were selected through simulation analysis. It provided a reference for the optimization design of steel belt packer in practical production and application.