Abstract: With employment of the ABAQUS FEA software,the finite element analysis (FEA) is conducted on the sealing characteristics of the commonly-used premium thread connection under simulated operation conditions, focusing on the sealing characteristics presenting under such combined conditions as thread screw-up,tensile,inner pressure and temperature,etc. The analysis result shows that under the operation conditions,the said thread connection always has its sealing surface with rather high contact stress,and its maximum equivalent VME stress value less than the yield strength of the material, the occurrence probability of leakage and galling of the connection in service is remarkably reduced.