As an organic whole, the earth is not only uninterrupted motion and change, but continual evolution. This evolution has its inherent laws. At present, the modern global system consisting of anthroposphere and global environment is lying in a new catastrophic stage.For this reason,it is very important for overcoming the global problem and achieving sustainable development to research the evolution of modern global system together with the earth's evolution. Three laws of the earth's evolution are discussed here, that is the law of stepped rise,the law of progressive increase of circulation form and the law of correlation between evolution and conditional optimization, and the relationship between three laws of earth's evolution and sustainable development is also discussed.