With the increasing complexity of the electromagnetic environment, the threats posed of electromagnetic weapons to electronic equipment are becoming increasingly serious. As a sensitive integrated electronic device, the optoelectronic system is coupled with high-power electromagnetic pulse energy. This can disrupt the normal operation of the optoelectronic system, especially when it lacks sufficient electromagnetic protection. To clarify the high-power microwave coupling process of typical optoelectronic systems including barrel type, side window type, multi-window type under different irradiation conditions, simulations and analyses are conducted. The characteristics of high-power microwave coupling in optoelectronic systems and their constraints are extracted. The necessity and urgency of protecting reinforcing optoelectronic systems with high-power microwave are verified. For addressing the issue of weak high-power microwave protection ability in optoelectronic systems, the simulation analysis verifies the effectiveness of reinforcing transparent electromagnetic protection windows for high-power microwave. The study focuses in the method of electromagnetic gap protection and reinforcement, which is based on the support step and the conductive side wall. The key parameters of the installation structure for the gap coupling leakage of transparent electromagnetic protection windows are analyzed, and a method of non-electric contact assembly gap high-power microwave protection and reinforcement method is proposed. When the length of the gap protection structure is 6 mm, the average high-power microwave protection efficiency of the 0.2-4 GHz optoelectronic system increases by 4.51 dB. The study provides theoretical guidance and specific solutions for enhancing the high-power microwave protection capability of optoelectronic systems.