To improve the information security level of the wide area protection system, the functions of the system and IED are analyzed. The communication data types of the system and their communication requirement are offered. The main security threatens and key information security technologies are analyzed emphatically. The key information security technologies include digital signature technology, encryption and decryption technologies, fire wall technology, intrusion detection and defending technology, VPN technology, et al. The problems that the information security of the wide area protection system should solve are presented. The information security standards of the power system are analyzed finally.