Abstract: Pearce's element ratio is a ratio of variable elements to constant element which didn't participate in the geological process to be studied in petrochemistry. In this paper, the authors discuss the comagmatic properties and differentiation processes of some Cenozoic basalts in Eastern China using the method: the eomagmatic property of potassium-rich basalts in Wudalianchi-Keluo area in Heilongjiang Province, the magma differentiation processes of Cenozoic basalts in Hannuoba and. Changbaishan areas, in Hebei and Jilin Provinces, respectively.The results show that the Pearce's element ratio can be used to study the origins and differentiation processes of basalts, and can be a good supplementary method to other traditional methods and have more replete and efficient use in whole-rock analysis.