Abstract：As a distributed technology, blockchain technology is widely used in the infrastructure of cryptocurrencies. It has the characteristicsof decentralization, non-tampering and traceability. It uses asymmetric encryption technology to ensure the security of data.As an important part of smart city, blockchain technology is no longer limited to the application in the financial field. The continuous development and update of blockchain technology has provided the possibility of integrating blockchain technology with other traditional fields. This article introduces the relevant concepts and data structures of blockchain technology, and discusses the core content of blockchain in detail, such as consensus mechanism, smart contract, Markle tree and asymmetric encryption, and applies the domestic blockchain technology to some traditional fields. The research on data security and data sharing is summarized.