Background of earth system science put forward was introduced firstly from three aspects which were global important problems for human being facing on, globalization of earth system and earth system science and traditional earth science. The study state at home and abroad of earth system science was expounded on above basis. Concept and study methods of earth system science were introduced in detail then. The contents are study thought, basic concept, process of earth system, globe-region information obtaining, magnanimity information processing and analysis and system models and so on. Thirdly, theoretical base of earth system science was constructed. The main contents included continual dynamical system of earth system, discrete dynamical system, randomicity of earth system, self-organization of earth system, simple giant system and complex giant system of earth system. Dynamics models and the offect of interaction between subsystem of earth system science and each circle were emphasized to be introduced. Fourthly, that digital express of earth system-digital earth and earth system science are base of sustainable development stratagem science was summarized. Finally, the study direction of earth system science developed in China and its main scientific problems facing on described briefly.