There are two parts in this thesis : In the first part (ch.2 - ch.4), we introduce Newton’s lifetime and how he invents the law of universal gravitation ; In the second part (ch.5 - ch.8), we re-prove the four important theorems of Newton’s law of universal gravitation by which Newton confirmed the equivalence of Kepler’s law of planets and the law of universal gravitation. One of the aim of our work is to explain Newton’s theorems to common reader. Hopefully, everyone can enjoy the beauty of Newton’s work.