在介绍三维复合力加载设备结构特点与工作原理的基础上,推导出复合力与单支链力之间的关系,建立了单支链电动缸力加载数学模型,通过仿真和实验研究了系统稳定性,分析发现小阻尼系数和力噪声是影响系统稳定与响应速度的主要因素,提出了一种改善系统稳定性和快速性的控制方法,并在实验中取得了良好效果,采用该控制方法,弯矩、轴向力复合加载频率可以达到10Hz. Based on the introduction of structural features and working principle of three-dimensional composite force loading device, the relationship between composite force and single-arm chain force is deduced, and the mathematical model of single-loaded chain electric cylinder force loading is established. The stability of the system is studied by simulation and experiment It is found that small damping coefficient and force noise are the main factors that affect the stability and response speed of the system. A control method to improve the system stability and fastness is proposed, and the good effect is achieved in the experiment. With this control method, Bending moment, axial force composite loading frequency can reach 10Hz.