With multi-beam method, this paper studies the interference of Newton's Rings and establishes the theory model of multi-beam interference Newton's Ring. Through the complex amplitude superposition of multi-beam coherent light waves, this paper obtains reflected light intensity formula and transmitted light intensity formula of multi-beams interference Newton ring. By numerical calculation, this paper describes the distribution intensity curves of reflected light and the distribution intensity curves of transmitted light under different reflectivity, simulates the interference fringe distribution pattern of reflected light and the interference fringe distribution pattern of transmitted light under different reflectivity. This paper shows that multi-beam method is applicable to the research of Newton's Rings under different reflectivity and transmitted light interference is used in the practical application, while selecting the moderate reflectivity.