Digital economy is the core and main symbol of the fourth industrial revolution, providing a new path to promote common prosperity for all people.This study constructs an evaluation index system of common prosperity from three dimensions of “prosperity”, “common” and “the relationship between common and prosperity”, and measures the common prosperity index of 270 cities in China from 2011 to 2019. On this basis, based on the quasi-natural experiment of the next-generation internet demonstration city policy, this study uses the difference-in- differences model to test the impact of digital economy on common prosperity.The results show that the next-generation internet demonstration city policy has significantly improved the common prosperity level of the demonstration cities, and stimulating entrepreneurial innovation and entrepreneurship is the important mechanisms for digital economy to promote common prosperity.The heterogeneity analysis results show that the next generation Internet demonstration city policy has a greater promotion effect on the common prosperity level of cities in central and western regions, cities in northern regions, cities with low administrative levels, smaller cities, and cities with a higher degree of marketization.This study not only enriches the theoretical research on the relationship between digital economy and common prosperity, but also provides a reference for the new journey to scientifically use digital technology to empower common prosperity.