As a special cryptocurrency based on value-stable attributes,stable coins not only act as a bridge to link blockchain crypto assets and real-world assets,but also have the potential to be an effective tool for reducing the cost of intermediary services in the real financial industry and improving the efficiency of capital transmission.Since the announcement of stable token programs by internationally renowned companies such as JP Morgan and Facebook,the stable coins have become a research hotspot for financial regulators,business circles and scientific institutions.By comparing the legal currency,cryptocurrency and stable coins,this paper introduces the characteristics of stable tokens in detail,and then introduces the system architecture and operation mechanism of stable tokens from three aspects of blockchain infrastructure,value stability and operation mechanism.Finally,we analyze the defects and possible solutions of the stable token system combined with its technical characteristics.