The environment and load condition of tubing is severe in high pressure wells. The sealability and joint strength of tubing string plays an important role in production operation. In this study, the makeup, sealability and joint strength was analyzed from conditions of make-up loading, tension loading, compression loading and internal pressure loading by finite element method. The makeup torque, the contact pressure distributions of metal seal along the axis and the stress distributions of threaded connection are given. The results show that under tension loading, compression loading and internal pressure, the overall stress level of threaded connection is lower than of pipe. The anti-compression performance and joint strength of threaded connection is greater than of pipe. The contact pressures of metal seal maintain relatively high level of contact pressures under tension loading, compression loading and internal pressure. Tension loading and compression loading reduces the sealing performance and the internal pressure increases the sealing performance from the integral of the contact pressure.