Taking the data of Shanghai and Shenzhen A?share manufacturing listed companies from 2012 to 2021 as sample， a two?way fixed effect model has been applied to investigate the impact of the digital economy development on enterprise investment efficiency. The research shows that the influence of its development on the investment efficiency presents a U?shaped nonlinear relationship， which is mainly manifested as the impact on enterprises with excessive investment， and that the development of digital economy can improve enterprise investment efficiency by reducing agency costs， whose impact on the efficiency is mainly reflected in large?scale manufacturing enterprises， manufacturing enterprises in the eastern region， and those enterprises with regional high marketization. Therefore， it is necessary to pay attention to the digital dividend resulting from the digital economy， accelerate the construction of digital infrastructure， optimize the business environment of the real economy， play the integration role between "effective market" and "proactive government"， and promote the integration between the digital economy and the real economy.