Abstract: This paper expounds the origin, concept, construction and development of digital twin earth, especially the integration of BeiDou Satellite Naviation System (BDS) and GF, digital twin and digital earth. Based on common information infrastructure such as communication and computer, the construction of digital twin earth is divided into six steps: full-chain credible space-time, holographic precision mapping, real-time ubiquitous perception, multi-module data fusion, single spatio-temporal intelligence, and all-domain shared intelligence and governance. In view of the distributed characteristics of spatio-temporal big data from collection to application, the “BDS + block chain” technology is proposed to solve the trust problem in business collaboration. It is pointed out that GF realizes the holographic image between the virtual and real earth, and BDS delivers the space-time datum for products of GF, realizing the accurate mapping between the virtual and real earth. In addition, BDS and GF are also the main technologies to realize space-time situation awareness. In view of the challenges brought by massive spatio-temporal big data to data operation and fusion, it is pointed out that grid location code of BDS is a more effective data organization mode. This paper introduces artificial intelligence and simulation driven by spatio-temporal big data, which can provide optimal scheme for planning, design and decision making. This paper analyzes the problems of duplication construction and resource waste of single intelligence, and points out that digital twin earth is the temporal and spatial base for the cross-border integration of various heterogeneous single intelligence and the realization of all-domain shared intelligence and governance.