Power system is the basis of the development of states. The security of the power information system must be guaranteed. In the power information system, most of existing security methods are based on encryption algorithms like RSA algorithm, up against the threaten of increasing computing power of Internet and quantum computer. According to the urgent demand for information security of power system and the unconditional security of quantum security communication, this paper explores the application of quantum security communication in power information system. Specifically, By detailed analysis of the procedure and security factors of the standard SSL protocol, this paper designed a security enhancement method which is compatible with the existing Internet protocol basis. The proposed method enhanced the source of random number by preset quantum random number (based on quantum random number generator or quantum key distribution network). Implemented on the OPENSSL VPN evaluation platform, experiments showed that the proposed security enhancement method could improve the security level of power information systems without tremendous increase in system complexity or cost.