The invention relates to a method of identifying Milankovitch cycle quantitatively. The method comprises the following steps of (1) selecting Gamma ray as a proxy indicator of Milankovitch cycle identification; (2) pre-processing Gamma data; (3) identifying theoretical orbital cycle value so as to acquire a theoretical cycle set M; and (4) identifying Milankovitch cycle in stratum, the specific process comprises following steps of first, organizing Gamma data in a target stratum; second, performing spectrum analysis on Gamma data in a selected stratum; and third, matching so as to obtain Milankovitch cycle and cycle thickness corresponding to the Milankovitch cycle.