Abstract: Residual current device (RCD) is increasingly widely used in electrical safety of civil buildings, but misoperation problems occur frequently, affecting power supply reliability and user experience. To improve the application effect of RCD, this study takes the electrical system of civil buildings as the research object. Through in-depth analysis of various factors such as selection and installation, line load, and equipment performance, the causes of RCD misoperation are systematically analyzed. An optimization configuration model based on objective function is proposed, and the feasibility of the improvement plan is verified through specific cases. The research results indicate that by adjusting the operating current threshold reasonably, installing harmonic filtering devices, and optimizing the circuit layout, the misoperation rate can be significantly reduced, while also considering safety and economy. This provides a scientific basis and practical reference for electrical safety management in civil buildings.