In this work, the design of the mechanical structure of a precision electric mirror frame is realized. Through the design and debugging of a micro-drive device and the decoupling operation of the parallel drive mechanism, the motorized mirror frame designed in this work achieves a motion stroke of ±7.5 mrad and a single-step resolution of 0.3 μrad. The finite element modal analysis of the mirror frame was conducted to obtain the natural frequency and the corresponding mode shape. Based on this analysis, the dynamic characteristics of the electric mirror frame were tested experimentally. Using the results of the modal analysis and dynamic characteristics test, the random vibration analysis of the mirror frame was conducted, revealing that the stability index of the mirror frame under the influence of ground pulse vibrations is better than 0.5 μrad.