Abstract: In order to study the influence of the aero-engine double-row curvic couplings' bending stiffness on the rotor dynamics, a double-row curvic couplings sector model considering the contact state is established. The bending stiffness characteristics of double-row curvic couplings are obtained; introducing the local stiffness nonlinear into the rotor dynamic equations, the rotor dynamics characteristics with double-row curvic couplings are obtained. The research results show the bending stiffness of double-row curvic couplings decreases with the increase of bending moment, showing obvious soft characteristics; the local stiffness nonlinearity of double-row curvic couplings reduces the bending critical speed of the rotor system by about 1%; The influence on rigid body vibration mode is less than 0.1%.In engineering practice, for the rotor system whose working rotation speed is higher than the bending critical speed, the influence of double row curvic couplings should be considered.