As the traditional data assets trading platform relies on the central management of the completion of the transaction process, it cannot guarantee the security of data assets in the process of transaction. Based on the technical characteristics of block chain technology: decentration, and unforgeability, this study proposes a new digital asset security transaction method based on block chain technology. Firstly, the drawbacks of traditional digital asset trading platform are expounded, and the key technology of block chain technology in data assets security transaction is analyzed. Secondly, from the perspective of data storage, transaction information, executive scheme is put forward. Finally, the verification algorithm of verification node in data transaction process is verified. The experimental results show that the proposed method in this study can be applied to digital asset security transaction.