The curvic couplings are widely used in aero-engine due to several advantages including accurate positioning, automatic centering and superior structural stability. However, the typical performances (i.e. stiffness and strength) of the curvic couplings are sensitive to the structural parameters and load parameters. Especially for aero-engine, the curvic couplings work in complex circumstances, such as high temperature, high rotating speed and continually varying speed, which greatly affect the stiffness and strength of the curvic couplings. Therefore, researching the stiffness and strength of the curvic couplings accurately is quite important. In this article, the high-precision three-dimension (3D) finite element model of the curvic couplings is established. Taking the effects of centrifugal force and bolt pre-tightening force into account, the bending stiffness and torsional stiffness are simulated and analyzed. The results are compared between the cases with and without the turbine disk.