As for steam seal rubbing fault phenomenon of highpressure rotor of 1 000 MW steam turbine shafting with N+1 supports,the rubbing force of rotorend steam seal was analyzed.By imposing the nonlinear constraints,the piecewise linear function of continuous collision forcedisplacement was taken to simulate the nonlinear contact stiffness in the process of rubbing,and the shafting dynamics finite element model with steam seal rubbing fault in the highpressure rotor was set up.The nonlinear steady synchronous response and transient frequency domain analysis were presented respectively,and the shafting response on the working speed of 3000 r/min and the vibration waterfall plots of bearings from the shafting with different rubbing stiffness were obtained.The results show that the vibration of bearings near the rubbing point is obvious,and the vibration characteristics of shafting response takes the 1X as the principal frequency among the operating speed range.Moreover,with the increase of rubbing stiffness,the 3X and 2X frequency components may exist,and the amplitude of each bearings may also decline gradually.