The main objective of the air-gapped network electromagnetic attack means is to establish a hidden connection channel with the external Internet. In recent years, the methods and tools which connect air-gapped network to Internet have been disclosed, and the corresponding analysis methods and detection methods have gradually been proposed by security teams at home and abroad. Comparing with network security vulnerabilities, electromagnetic vulnerabilities are defined as electromagnetic factors that can cause effect or damage to devices or systems. Taking physically isolated network as an example, electromagnetic vulnerabilities mainly refer to the hardware and system defects of the network. Using these defects, a covert channel through the implantation of malware can be established directly, which can break through physical isolation by sending and receiving electromagnetic signals. Through extensive vulnerability mining and verification, the classification method of electromagnetic vulnerabilities in air-gapped network is proposed from the aspects of physical signal type, information transmission direction, signal generation mechanism, vulnerability utilization mode and vulnerability detection method. The comprehensive reference of network security vulnerabilities, electromagnetic information security detection and air-gapped covert communication is provided. From the perspectives of deepening active detection, group intelligence vulnerability mining, network electromagnetic security integration, and big data monitoring, the establishment method of electromagnetic vulnerability database for air-gapped network is proposed.