The Upper Palaeozoic source rocks in Jiyuan-Zhongmou-Huangkou depression belt experienced complicate structural and thermal evolution.The three depressions were similar in thermal history before the Middle Triassic

but the differential subsidence during the late of the Jurassic-Cretaceous period led to their difference in thermal evolution of the Upper Paleozoic source rocks.Jiyuan depression suffered no or tiny uplifting after the Triassic and received continuously Mesozoic and Cenozoic deposits.The Jurassic-Eogene period is its main hydrocarbon generation stage.Zhongmou depression passed through extensive subsidence since the Cenozoic resulting in continuous rising of the temperature of the Palaeozoic.The Eogene is its main hydrocarbon generation period.Huangkou depression began to subside since the Jurassic and subsided again in the Late Eocene.Its thermal maturity is low and the Cretaceous-Eogene period is the main stage of hydrocarbon generation.