Northern Hebei Western Liaoning, developing in boundary between Jurassic and Cretaceous with various fossils and volcanic ash bedding, is the marvelous region for the study of lithological, biostratigraphic, isotopic dating and Magnetic chronostratigraphy. The boundary of Jurassic and Cretaceous strata are between the Dabeigou and Dadianzi formations in the Luanping Basin, Northern Hebei and the Tuchengzi and Yixian formations in Yixian Beipiao area in Western Liaoning. The Dadianzi Formation consists of spore & pollen assemblages, such as Cicatricosisporites Luanpingspora Jugella; Ostracoda: Yanshanina Cypridea Rhinocypris assemblages, Cypridea Yanshanina Timiriasevia assemblages, Cypridea sulcata sub assemblages and conchostraca: Eosestheria Abrestheria assemblages and so on. Those fossils can be correlated in home and aboard, especially, spore & pollen and ostracoda are the same fossils in the correlation strata in England, French, Germany, Russia and Canada, with age of Early Early Cretaceous (Berriasian). However, the spore & pollen and conchostracain developed mainly in the lower part of the Yixian Formation are same as those assemblages in the Dadianzi Formation. Then, the Dabeigou Formation with spore & pollen assemblages: Poceites Podocarpidites Schizaeoisporites assemblages, Ostracoda: Luanpingella Torinina Eoparacypris assemblages and conchostraca: Nestoria Keratestheria assemblages show the Late Late Jurassic period (Tithonian) in the correlation with home and aboard. However, the boundary of Jurassic and Cretaceous is just developed in between the Dabeigou and Dadianzi formations. In the International biostratigraphic correlation shows the boundary between Jurassic and Cretaceous, eg. the boundary of the Tithonian and Berriasian. According to the isotopic data in North Hebei Western Liaoning region, the boundary age of Jurassic and Cretaceous is at 1307 Ma.