In oil and gas exploration, the safe production of high-temperature and high-pressure gas wells is of vital importance. The sealing performance of wellhead devices directly affects the efficiency and safety of oil and gas production. This paper conducts an in-depth analysis of the sealing performance of the commonly used BT seal structure under high-pressure testing conditions. By employing finite element analysis software, the sealing characteristics of the BT seal under test pressure are investigated, revealing its mechanical behavior under different pressure conditions. The results show that the BT seal exhibits excellent sealing performance under test pressure, with a maximum Mises stress of 52.02 MPa and a maximum contact pressure of 65.2 MPa. Additionally, suggestions for optimizing the BT seal structure are proposed to further enhance its sealing performance and reliability. This study provides a theoretical basis and technical support for the safe production of high-temperature and high-pressure gas wells.