The invention discloses a keyless shared automobile system based on a blockchain technology and a construction method thereof. The system comprises an application layer, a blockchain layer, a data storage layer and a physical layer; the application layer comprises a user management module, a vehicle management module and an order management module; the blockchain layer consists of several connected blocks, and includes a smart contract template for performing user information registration and order contract terms; the data storage layer is used for storing user information, automobile information and order information, and hash values and storage locations of three information raw data are stored by the blockchain layer; the physical layer includes a mobile terminal and an automobile terminal, a user sends an unlock request through the mobile terminal, the automobile terminal includes am automobile networking system and an automobile smart lock, the automobile smart lock is used for unlocking, and the automobile networking system is used for recording and uploading driving data. The system enables an owner and a renter to complete the issuance and receipt of an order through the smart contract without the need of third party participation, and reduces the transaction cost.