The earth system science that was put forward as an integrating method to meet the challenge of global environmental issues in the 80's and that has gradually become a new rising discipline recently is described in this paper. The objectives, the research target, methodology as well as the scientific issues are also described. The earth system science is a trans-discipline that links with the earth science, life science, computer science and space observation of the Earth as well as other related disciplines. It is also a discipline with great vitality due to its concern of the special global environmental issues which are closely related to sustainable development of society and human benefits.