This article conducts design and optimization research on the structure of a return force linkage actuator. A kinematic model of the return force linkage actuator was established, and based on this, the relationship between the effective rocker arm radius and the geometric parameters of the linkage actuator was given. The accuracy of the constructed kinematic model was verified through simulation using Adams. The kinematic model of the return force linkage actuator constructed in this article was compared with the point-to-point installation form, demonstrating the outstanding performance of the return force linkage actuator constructed in this article in improving the stiffness of the actuator. The particle swarm optimization algorithm was applied to optimize the geometric parameters of the return force linkage actuator, thereby improving the effective rocker arm radius of the actuator. Finally, experimental verification was conducted on the optimized parameters. The results indicate that the optimized geometric parameters have achieved the goal of reducing weight and improving stiffness.