<p>The dynamic characteristics of the stator system have a significant impact on the behavior of aero-engine rotors, and the coupling of rotor, support, and stator vibrations is a key issue in rotor dynamics. While dynamic stiffness is commonly used in engineering practice to represent the stator’s influence on the rotor’s dynamics, the coupling mechanisms between the rotor system, nonlinear support components (such as bearing and squeeze film damper), and the dynamic stiffness of the stator remain unclear. This paper presents a nonlinear rotor-bearing-SFD coupling model that integrates the dynamic stiffness of the stator, focusing on the impact of dynamic stiffness on rotor modal characteristics and nonlinear behavior, including critical speeds, amplitude-frequency response, bifurcation behavior evolution, and support system load-bearing characteristics. Experimental validation is conducted using an aero-engine rotor-support-casing tester. Simulation and experimental results show that considering stator dynamic stiffness significantly alters the rotor’s critical speeds and amplitude-frequency response while reducing the system’s nonlinearity compared to static stiffness. This study highlights the importance of considering both stator dynamic stiffness and the nonlinear characteristics of supports in aero-engine rotor modeling.</p>