Abstract: Revealing the dynamic characteristic mechanism of the rubber isolation pad (RIP) with different preloads and thermal oxygen aging conditions is the key to match the vibration isolation system of the air conditioner compressor. The Peck model is first introduced to characterize the thermal oxygen aging factor, and the fractional derivative Kelvin-Voigt perturbation model and the Coulomb friction perturbation model including the thermal oxygen aging factor are established to describe the frequency dependence and the amplitude dependence, respectively. The model for the thermal oxygen aging-dynamic characteristic of the RIP is built by considering the influence of variable preloads. The model parameters under different preloads are further identified, and the correctness of the model is verified by the experimental data. The concepts of stiffness transition points and stiffness transition frequencies are innovatively proposed to better describe the softening effect of the RIP under variable preload and amplitude conditions after service. These can lay a theoretical foundation for the in-depth study on the stiffness matching of an air conditioner compressor with the RIP and on the optimization design of rubber formula.