Aiming at the problem of data being easily copied and the realization of data confidentiality in current data trading process, a data trading scheme based on blockchain and trusted computing was proposed. First, the blockchain was applied to record data information, trading information and data usage records, which facilitated to confirm the rights of data assets and data provenance. Then, the trusted computing and encryption algorithms were used to ensure the security of the trading data transmission. Finally, the algorithms provided by the data owners and demanders were applied to complete the calculation in the trusted computing environment, after that, the results were output and encrypted to return to the demanders. In the proposed scheme, the demanders can use the data for calculation without revealing data from the data subjects, and the transmission security is guaranteed through trusted encryption.