Under the dual pressure of the economic crisis and technological changes, major changes took place in the global monetary and financial system. This paper uses philology to study the application of blockchain technology in digital currency, aiming to grasp the current situation and the main development direction of digital currency. The results show that digital currency research is in rapid development stage with obvious regional characteristics; security and privacy of digital currency, blockchain technology consensus algorithm, energy consumption of blockchain in mining process, transaction security based on Ethernet smart contract, financial supervision of digital currency, and machine learning in digital currency are the six main research contents of blockchain technology in digital currency application. In the future, blockchain technology faces severe challenges in the research of encryption technology, security development of smart contracts, consensus mechanism, scalability, financial supervision and other aspects. Through this research and outlook, we hope to guide the future development of blockchain technology in the digital economy.