This paper simplifies the model of steam turbine rotor and establish a simple calculation model to calculate the temperature distribution of rub section according to the rotor rub theory which can greatly simplify the calculation. Therefore, the thermal bending model induced by rotor?to?stator rub is established. The rotor motion equations are derived according to the rotor dynamic theory, and non?dimensionalized to improve MATLAB numerical solution convergence. The fault dynamic model is then coupled with thermal bending and the rub of the rotor system is established. Finally, the differential equations are solved based on the Runge?Kutta fourth?order numerical integration method to obtain the rotor system response, such as unbalance force, rub force and thermal bending moment. This paper gives the vibration characteristics including the time domain diagram, frequency domain diagram, orbit diagram and the changes of rubbing forces with speeds below, close to and above the critical speed. It is found that if the rotor rubs move in the speed below and close to the critical speed, the vibration of rotor diverges gradually from steady state, while for that above the critical speed, the vibration decreases gradually.