Abstract: As the tracking precision of photoelectric seeking system decreases with the structural distortion under vibration and impact shock, it is essential to study the dynamic characteristics and to optimize the structure system using Ansys software. The structures finite element analysis (FEA) model was established and its feasibility was validated by modal testing results with laser Doppler velocimetry (LDV). On the basis of the simulation results under impact shock conditions, the relations of angle and angular velocity of reflector to the attitude axle are clarified and the structure is optimized to meet the design requirements.