This article comprehensively analyzes the issuance background, main features, technical architecture, and the impact on commercial banking operations and regulatory systems of China's Digital Currency Electronic Payment (DCEP or e-CNY). E-CNY is a legal digital currency that has the essential functions of money and a centralized two-tier operating system, making it compatible and stable with the current financial system. The article first outlines the main characteristics of e-CNY, reviews in detail the research and development process and pilot situations since 2014, and demonstrates its application progress in various scenarios. Furthermore, the article delves into the profound impact of e-CNY on commercial banks' deposits, loans, and international operations, suggesting that e-CNY may reduce the deposit base of commercial banks while providing Chinas small and medium-sized enterprises (SMEs) with a lower-cost financing channel, thereby promoting the development of the real economy. On the international front, promoting e-CNY is expected to enhance cross-border payments' efficiency and strengthen CNY's international competitiveness. Subsequent analysis of the practice of China Construction Bank (CCB) in the field of e-CNY showcases how commercial banks adapt to the era of digital currency. It also points out the need for further clarification and improvement of the regulatory framework to ensure the sustainable development of e-CNY. Finally, particular attention is given to the regulatory challenges e-CNY poses, especially regarding anonymity management, personal information protection, and delineating regulatory responsibilities.