The Early—Middle Jurassic strata in Northwestern Hebei even though has been researched for a long history, but t is still different with that in western Beijing (in the same region——Yanshan orogenic belt) as to the specific division and correlation. The strata in Northwestern Hebei area are divided into Nandaling Formation, Xiahuayuan Formation, Jiulongshan Formation,Tiaojishan Formation and Houcheng Formation while in the western Beijing area the strata that is considered the same layer to the Xiahuayuan Formation are divided into Yaopo Formation and Longmen Formation. Writers consider that,there is also the Longmen Formation in Northwestern Hebei area, the same layer to that in western Beijing, which are used to be considered as a part of the Xiahuayuan Formation or the Jiulongshan Formation. Writers also find that the Xiahuayuan Formation still contains a part of the Nandaling Formation. In this paper，the conclusions of a redivision are as follows: the Lower Jurassic Nandaling Formation, the Middle Jurassic Xiahuayuan Formation, Jiulongshan Formation,Tiaojishan Formation and Houcheng Formation, and they can be completely correlated with those in western Beijing area. These conclusions are very important to the establishment of the Early—Middle Jurassic stratigraphic framework and the study of the tectonic evolution in the Yanshan region．