Nowadays, more and more banks and other financial service companies are promoting digital currency transfers and other online transactions, which are wire transfers or transfers between parties over long distances. Digital currency contributes to the globalization of the global economy because it is easier to trade by sending and receiving digital currency. [1] The Technology underlying Money continues to evolve, and many scholars and experts are concerned about the development of the digital currency. Through the research of domestic and foreign digital currency literature and related information, this article summarizes the concept, classification, characteristics and benefits, risks and potential problems of digital currency, and finally gives an overview of the development trend of digital currency. In a broad sense, digital currency is any form of money or payment that exists only in spreadsheets. And digital currency could be classified as cryptocurrency, virtual currency and central bank digital currency(CBDC). They are usually decentralized and anonymous. The features enhance the security of users. Digital currencies offer enhanced security, greater convenience and compatibility, making up for the drawbacks of cash. Market risks, security risks, law risks, bank risks and risks for producers are the main risks that digital currency brings. According to much research, CBDCs which can maximum to limit the risks of digital currency might be the main trends of digital currency's future.