Purpose <p>Conducting the attitude adjustment tests of the solar array on the ground is highly significant. However, the introduction of the gravity unloading system that can meet large-amplitude movements will cause changes in the dynamic characteristics of the system. This paper aims to guide the design of the unloading system by analyzing its influence and verify the reliability of the ground experiment.</p> Methods <p>Polycondensation and Lagrangian energy method are used to establish a low-degree-of-freedom model, which can reflect the dynamic characteristics of the ground attitude adjustment system. Eigenvalue analysis and system response analysis are used to analyze the influence of the unloading system and its parameters.</p> Results <p>Through eigenvalue analysis, it is found that the magnetic-pneumatic suspension unloading system adopted in this paper will introduce an additional mode to the attitude adjustment system, causing the original fundamental frequency of the system to split into two. By selecting a small mass for the hybrid magnetic element, the fundamental frequency error between the ground and space systems can be controlled within an acceptable range. The additional mode will be introduced at a relatively high frequency, minimizing its effect. Through the analysis of the response, it is found that the maximum value of the response of the system in the ground test state is mainly determined by the driving impact and is less affected by the unloading system. Therefore, it can reflect the space state well. However, due to the unloading system, both the fundamental frequency and the damping ratio show a decreasing trend, which will reduce the decay rate of the system, and will decrease further with the increase of the mass of the hybrid magnetic element. In addition, the synchronization of the vibrations between the simulator and the unloading system is also affected by the mass of the hybrid magnetic element.</p> Conclusion <p>By reasonably designing the unloading system, the ground test system for the attitude adjustment of the solar array can achieve dynamic characteristics similar to those in the on-orbit state. The work carried out in this paper demonstrates the reliability of the ground test and provides certain theoretical support for the implementation of the design work.</p>