Abstract: With the development of social economy, the civil airport has put forward the construction goal of "four type airport". This paper analyzes the causes, transmission mechanism and influence mechanism of voltage sag in combination with the characteristics of civil airport power supply and distribution grid and related power loads, and puts forward the treatment ideas, relevant treatment equipment and technical schemes of voltage sag from the management and technical levels, so as to further improve the management level and anti risk ability of civil airports to deal with voltage sag, Ensure the stable and reliable operation of all important systems and equipment of the airport, and improve the service level and window image of the airport.