The invention relates to a blockchain-based network security auditing system and a blockchain-based network security auditing method. The network security auditing method comprises the steps that: anauditing server applies for a signature public/private key pair and a secret key to a secret key management server, a block generation server of the blockchain applies for a signature public key to the secret key management server, the auditing server acquires data to be audited and encrypts the data to be audited to generate C1, re-encrypts an encryption secret key to generate a C2, and performing digital signature on the C1 and the C2 by means of the private key to generate sigma; and the auditing server transmits the C1, the C2 and the sigma to the block generation server, the data to be audited is placed in a data buffer region after the C1, the C2 and the sigma are verified to be valid by using the public key, generates a new block and broadcasts the new block when a block generationcondition is met, and a display terminal can request the block generation server to view the audit data. The blockchain-based network security auditing system and the blockchain-based network securityauditing method utilize the blockchain technology, and adds the blockchain into the auditing system, thus the audit data cannot be tampered, the data security is improved, the audit data in the blockchain is encrypted to ensure that the audit data can only be accessed by authorized users, and the confidentiality of the audit data is protected.