In this paper, a mirror with 400mm aperture is taken as the research object. A test system and experimental method for the study of the mechanism of action between the surface shape of the mirror and the actuating force are designed. The system is composed of five parts: optical element, the metering type surface shape control device, a stress-strain testing system, a measuring device for the mirror surface shape and a multi-dimensional translation table. Firstly, the support mode of φ400mm aperture plane mirror is determined by means of optically integrated analysis technique. Secondly, the design of the metrological surface shape control device is completed. The metrological surface shape control device can realize the micro-stress support of the mirror and provide the initial state for the experimental study. At the same time, the actuator component on the back can test and display the driving force in real time. Thirdly, with the mirror shape as the optimization target and the force applied on the back of the mirror as the control variable, the size of the force can be obtained by using the optic-mechanical integrated analysis technology for simulation optimization. In the experiment, the mirror shape can meet the expected requirements by applying the corresponding tension or pressure through the back actuator. In addition, set up a mirror surface shape - promoting the motivation mechanism research and testing system. The research flow of mirror shape regulation mechanism is put forward, through reflection mirror shape detection, the form data processing, and actuating force calculation, and the power, surface shape control effect assessment, through several rounds of iteration calculation and adjustment, realize the regulation and optimization of reflection mirror. The experimental system and method proposed in this paper provide a theoretical basis for the further study of active control technology of large aperture mirror. © 2023 SPIE.