Low-carbon development has become an important trend of economic development all over the world，and digital economy is an important starting point to achieve the goal of peak carbon dioxide emissions and carbon neutrality in China. Therefore，it is of great practical significance to study the digital economy to promote the low-carbon transformation of Beijing-Tianjin-Hebei urban agglomeration. This report first analyzes the status quo of digital economy development and carbon emission in Beijing-Tianjin-Hebei urban agglomeration. On this basis，the relationship between digital economy development and carbon emissions in Beijing-Tianjin-Hebei urban agglomeration is studied by building a panel regression model. The results show that the registered capital of the digital economy service industry in Beijing-Tianjin-Hebei urban agglomeration is on the rise，and the innovation achievements are greatly increased. Among them，the development scale of digital information transmission industry ranks first，but the development trend is slowing down. The development structure of digital economy service industry in Beijing，Tianjin and Hebei is different. Beijing is dominated by digital information transmission industry，while Tianjin and Hebei are dominated by digital technology service industry. The carbon emissions of Beijing-Tianjin-Hebei urban agglomeration are on the rise，and the distribution is uneven. Hebei’s carbon emissions are much higher than those of Beijing and Tianjin，and are constantly increasing. Tianjin’s carbon emissions are slowly rising in fluctuations，and Beijing has successfully completed the peak carbon dioxide emissions target in 2012. The carbon emission intensity of all prefecture-level cities in Hebei is higher than that of Beijing and Tianjin，which has increased the overall carbon emission intensity of Beijing-Tianjin-Hebei urban agglomeration to some extent；Beijing’s tertiary industry consumes the most energy，while Tianjin and Hebei consume the most energy in the secondary industry，and their industrial energy consumption structures are different. The development of digital economy has significantly reduced the carbon emissions of Beijing-Tianjin-Hebei urban agglomeration. On this basis，this paper puts forward some countermeasures and suggestions for digital economy to promote the low-carbon transformation of Beijing-Tianjin-Hebei urban agglomeration.