In recent years, digital currency has experienced rapid growth and garnered widespread attention from various sectors. By reviewing its developmental trajectory—from early conceptualizations and theoretical foundations, to the emergence and rise of Bitcoin, the exploration and implementation of central bank digital currencies (CBDCs), and the proliferation of alternative cryptocurrencies—this paper outlines the key stages in the evolution of digital currency. It highlights current challenges such as privacy protection and regulatory issues, while projecting future advancements in technological innovation, regulatory frameworks, and expanded application scenarios.