Abstract: Frequent onlap-denudation areas are characterized by frequent stratigraphic overlap, rapid lithological change, and developed fracture systems, thus are considered to be favorable zones for formation of stratigraphic oil-gas reservoirs. This study is focused on the unconformity characteristics and trap development models in frequent onlap-denudation area by taking an example of the upper fourth sub-member of Shahejie Formation (Es₄^s)-Dongying Formation(Ed) in northern Caoqiao area. The sequence, horizontal unconformity characteristics and longitudinal lithological configuration characteristics, as well as unconformity control over on stratigraphic traps in the study area are investigated. The Es₄^s-Ed formations is divided into six third-order sequences, 16 system tracts, and 24 parasequence sets. There are six unconformities of three different levels, including four types:denudation-onlap unconformity, parallel-onlap unconformity, denudation-parallel unconformity, and parallel unconformity. The first-order unconformity has developed three layers of structures, i.e., rock above the unconformity, weathering claystone, and semi-weathered rock; and the other lower-order unconformities have developed two layers of structures without weathering claystone. The control of unconformity over the stratigraphic traps depends on the combination of plane type and longitudinal structure of the unconformity. A trap model of frequent onlap-denudation area is established, which indicates that in sequences mainly developed with sand bodies (e.g., delta and fan delta), the lowstand system tract is favorable for the formation of stratigraphic onlap traps, while the highstand system tract is favorable for the formation of unconformity block traps; in sequences mainly developed with claystone deposits (e.g., lacustrine facies), the lowstand and transgressive system tracts are favorable for the formation of fault-lithological and fault traps, while the highstand system tract is favorable for the formation of unconformity block traps.