Blockchain Security Report “Safety Issues in the Rapid Development of Blockchain + Industry” was released. The report analyzes and interprets the security issues facing the blockchain industry. From the perspective of technical security, blockchain faces the risks and challenges of algorithm security, protocol security, usage security, security and system security. From the perspective of vulnerable points, the economic losses caused by blockchain security attacks mainly focus on smart contracts, consensus mechanisms, trading platforms, users themselves, miners, and consensus mechanisms. From 2011-2018 to the present, the cumulative loss of security incidents at the level of smart contract was US$1.409 billion, accounting for 42.04%, the loss of trading platform security incidents was US$1.345 billion, accounting for 40.15%, and the loss of common user security incidents was US$437 million. 13.03%.