Abstract: Different multiaxial creep experiments were conducted on P92 steel tube samples under combination loading of inner pressure and tensile at 650℃ and the creep behavior was simulated by modified Kachanov-Robatnov creep model. The fracture morphology and microstructure were observed and the influence of multiaxiality on stress distribution and damage evolution of P92 steel was analyzed. The results show that the higher the multiaxiality, the shorter the creep lifetime of P92 steel subjected to combination loading of inner pressure and tensile was when the equivalent stress on the outside of tube was the same. The modified Kachanov-Robatnov creep model could describe the creep behavior of P92 steel accurately. Multiaxiality influenced the stress distribution, and then affected the distribution of damage during creep. The position with the largest multiaxiality had the largest damage.