Abstract: The encrypted protection on the transmission line of substation comprehensive information data is not enough to resist malicious attacks, and the core information is easy to leak in the transmission process. Aiming at the poor security and anti attack performance of substation comprehensive information, a data encryption method for substation comprehensive information based on improved Blowfish algorithm is proposed. The Blowfish algorithm is used to encrypt the comprehensive information data of the substation, and the 512 bit grouping processing method is used to fill in the comprehensive information data of the substation; Innovatively combine MD5 algorithm with Schnorr authentication protocol, build a dynamic and static combination of ciphertext knowledge proof mechanism, and generate environment parameters to ensure the security of the protocol; The improved Blowfish algorithm is used to realize the encryption and decryption of the comprehensive information data of the substation, and the key change event is triggered by the timer to update the key regularly; According to the standards of the International Electrotechnical Commission, use the Blowfish algorithm to send the key status application to the substation, and run the data key update process; The hash algorithm is used to judge the change of key and prevent information from being peeped and modified during transmission; The information data is attached with identity information transmission, and the key of the improved MD5 algorithm is encrypted with the key of the Blowfish algorithm to ensure the security of the comprehensive information data of the substation. The experiment shows that this method can effectively encrypt the comprehensive information data of substation; The average value of the difference of the autocorrelation coefficient has reached 0.102, which has high anti attack performance and decryption efficiency, can better protect the privacy of the comprehensive information data of the substation, and has high security.