The Deep-time Digital Earth (DDE) is a big science program aimed at transforming Earth science research by integrating big data and advanced technologies. Launched in 2019, DDE seeks to build an open-access digital platform that compiles geological and paleontological data from Earth's deep history, spanning billions of years. This initiative fosters collaboration among scientists worldwide, enabling them to address fundamental questions about Earth's evolution, climate change, biodiversity, and resource distribution.