Whether digital assets represented by Bitcoin are monies determines whether they are constrained by public and private laws related to monetary payment. Digital assets do not depend on the fiat money system, do not limit scope of using, and have strong nature of decentralization, which bring greater challenges to the definition of the concept of money. In the case that the existing law only stipulates that Renminbi is the legal tender, and only provides the extension of money for "monetary form" and "monetary asset", China's regulatory stance that digital assets are not monies fails to follow the principle of same business, same risk and same supervision, so it is difficult to protect the payment expectation of the parties and promote further innovation in digital payment. Based on the unclear positioning of the country and the market in the monetary circulation as well as the purposes differences among different legal branches, it is not suitable for the monetary theories in economics and sociology to directly define the legal concept of money. Besides, the quasi-monetary theory and the monetary identity theory created by legal scholars also have many limitations in the preconditions and the scope of application. The modern monetary payment system has formed the stratified characteristics of fiat money, payment means denominated in fiat money, as well as payment means not denominated in fiat money. The monetary stratification system is essentially a mixture of state and market as well as public and private, with the state at the top of the system and fiat money as the most creditworthy type of money. Under that system, the legal concept of money is not identical, nor can it be limited to fiat money. Instead, the legal connotation of money should be defined as "element of payment system" which is used to pay off monetary debts and can be generally accepted. This connotation may distinguish money from investment instrument, monetary medium, and means of payment that are accepted by only a few people or within a small area. More specifically, referring to the relevant market and market share theories under the anti-monopoly law, the generally accepted market range can be identified from sub-service market, using accessibility, another money which may be replaced, while the generally accepted degree can be identified through the stabilization mechanism of monetary value and the number of merchants accepting the money. On the other hand, the legal denotation of money includes fiat money which has the legal tender effect under the Constitution and the central bank law, and other means of payment which has the effect of payment supervision under the payment service law and anti-money laundering law, or has the effect of monetary property under the law of collection of administrative expenses as well as property protection. More specifically, with the rise of digital assets and central bank digital currencies, the composition of the monetary stratification system is richer, and the number of monies with the effect of payment supervision and monetary property will increase.