It is a big jump for the currency form from the initial general equivalent to digital currency. This article interprets the evolution of currency from the perspective of efficiency, fairness and legitimacy, and then discusses its shocks to current transactions. Private digital currency can not fully perform the five functions of currency particularly “fair value”. Being contrast to the Hayek’s statement that free competition would undoubtedly produce the optimal currency, however, currency denationalization triggers market chaos. Besides, the currency reflects both economy and politics, and the monetary order to some extent affects the benefit distribution. Digital currency is not a new species in the currency world. It is actually more efficient, but its service capacity is limited due to its inability in providing fairness and controversy over legitimacy. Central bank digital currency is a new type of currency nationalization. It will become an essential carrier to improve the national economic and political status, serve the higherlevel goals of the monetary system and the international monetary system, and provide new possibilities for international and regional monetary cooperation.