Steam turbines are widely used in electric power, petroleum, petrochemical and aviation industries. The rotor system is a key component of the steam turbine. Because the turbine rotor structure is more complex, high working speed and complex temperature environment of the rotor system easily lead to excessive vibration, rubbing, crack, fracture, other serious accidents and even units damage, resulting in loss of personal and economic property. Through the establishment of a dynamic finite element model for the steady⁃state vibration response of the bending moment excitation of the turbine rotor⁃bearing system, calculation of steam turbine rotor bending moment for steady⁃state vibration displacement and stress response curve, analyses the size and location of bending moment on the influence of steam turbine rotor steady⁃state vibration response, providing theoretical basis for design of steam turbine rotor system dynamics.