Abstract: How to define the legal attributes of digital currency involves many legal issues such as civil law, bankruptcy law and even financial transaction law. Bitcoin, as an electronic payment system based on the principle of cryptography, exists in the virtual space of computer network. It is obviously not a physical object in the traditional civil law. Digital currency becomes an object of ownership. As long as it can satisfy the owner's control and governance, ownership can have all the contents of possession, use, income and disposal. Ownership and its change can be publicized in a clear way. Japan and China's private law system are roughly the same, and the understanding of digital currency is roughly the same. Some of the practices of Chinese courts in judicial practice are ahead of Japan. However, Japan's legislation in recent years has a more proactive attitude. China has completely banned digital currency transactions and ICO. In future legislation, serious consideration should be given to whether digital currency related issues are included in the current legal system.