A blockchain-based privacy transaction method, applied to a node device of a trusted user, wherein the trusted user belongs to a plurality of trusted users selected and set by a blockchain user of a blockchain based on trust of the blockchain user to the plurality of trusted users, the trusted user is selected by the blockchain user from the plurality of trusted users and a trust setting transaction stored in a distributed database of the blockchain comprises identifiers of all trusted users of the plurality of trusted users, wherein the identifiers of all the trusted users of the plurality of trusted users uniquely determine information about all the trusted users of the plurality of trusted users and the method comprises: receiving a first message sent by the blockchain user, wherein the first message comprises privacy-unprotected first data information; converting the privacy-unprotected first data information into privacy-protected second data information; storing the privacy-unprotected first data information in a local database of the node device of the trusted user; sending a second transaction to the blockchain, wherein the second transaction comprises the privacy-protected second data information, so that the second transaction is recorded in the distributed database of the blockchain after being verified; obtaining the trust setting transaction from the distributed database of the blockchain; determining other trusted users trusted by the blockchain user based on the trust setting transaction; and transmitting, in an off-chain method, the privacy-unprotected first data information and the privacy-protected second data information to node devices of the other trusted users so that the privacy-unprotected first data information is stored in local databases of the node devices of the other trusted users after it is verified that the privacy-protected second data information is converted from the privacy-unprotected first data information. receiving a first message sent by the blockchain user, wherein the first message comprises privacy-unprotected first data information; converting the privacy-unprotected first data information into privacy-protected second data information; storing the privacy-unprotected first data information in a local database of the node device of the trusted user; sending a second transaction to the blockchain, wherein the second transaction comprises the privacy-protected second data information, so that the second transaction is recorded in the distributed database of the blockchain after being verified; obtaining the trust setting transaction from the distributed database of the blockchain; determining other trusted users trusted by the blockchain user based on the trust setting transaction; and transmitting, in an off-chain method, the privacy-unprotected first data information and the privacy-protected second data information to node devices of the other trusted users so that the privacy-unprotected first data information is stored in local databases of the node devices of the other trusted users after it is verified that the privacy-protected second data information is converted from the privacy-unprotected first data information.