From the perspective of the Network Security Law, compared with the Internet, blockchain's innovative technologies and their applications, such as distributed ledger, have a higher level of network security. With more technical measures adopted, the security of blockchain would be further strengthened. However, blockchain technology and its applications are not absolutely secure; hence, the coupling of technology and law to ensure blockchain security has become an urgent issue. Therefore, we should attach great importance to the security application of blockchain, build a system of blockchain security to guarantee the rule by law with the idea of “zero trust security”, solve blockchain's legal security issues respectively based on the characteristics of private chain, alliance chain and public chain, use legal methods to facilitate the innovation of blockchain technology, promote international cooperation in policies, standards, rules and mechanisms, and put the concept of a community of shared future of mankind in cyberspace into practice.