<p>The success of lunar landing missions critically depends on the faithful reproduction of the target celestial body’s mechanical environment through ground simulation tests, particularly during the critical touchdown phase of the lunar lander (LL). To accurately simulate lunar gravity conditions during the dynamic descent of the LL on Earth, this paper proposes an adjustable-lever-arm constant spring support (ALA-CSS). This mechanism achieves dynamic compensation for potential energy changes. A dynamic model of the ALA-CSS is established, and its nonlinear dynamic characteristics are analyzed in detail. An inverse-based feedforward-feedback (IBFF) control strategy, integrated with a force feedback controller, is developed to simulate the entire LL touchdown process. This approach thereby ensures that an 83.3% gravity unloading ratio is maintained throughout the entire sequence, from the free-fall phase to the touchdown damping phase. The LL maintained precise lunar gravity characteristics during a 2m free-fall, followed by touchdown damping at a height of 0.15&#xa0;m. A smooth transition in the unloading control is achieved between these two phases. Digital experiments demonstrate that in Earth-based dynamic unloading scenarios, the proposed scheme offers high precision and fast response. The results are further validated by a multibody dynamics simulation using ADAMS, confirming the effectiveness of the proposed mechanism and control strategy.</p>