Combing the structure dynamic design method with the control theory, the flexible electromechanical coupling control model was built which is difference from the traditional rigid control model. The relationship between the structural fundamental frequency and servo bandwidth was analyzed, then the dynamic quantitative design principles were put-forward, The experiment results show that, the theodolite structure frequency should be far away from the resonant frequency of the system, and meet ωn≥3ωr at least, which is effective and feasible, has solved the high precision large theodolite electromechanical resonance problem, and provide the basis of engineering for designing fast response and high tracking precision of photoelectric theodolite.