The formation and distribution of hybrid event beds, common in lacustrine basins, is significant for understanding the evolution processes of gravity- flow, conventional and unconventional oil and gas exploration, and development of deposits within. Considering the gravity- flow deposits in the first member of the Liushagang Formation in the Weixinan sag, and the seventh member of Yanchang Formation in the Ordos basin as examples, the sedimentary characteristics, types, formation mechanisms, depositional model as well as the oil and gas geological significance of hybrid event beds in lacustrine basin are discussed. The gravity- flow deposits in the lacustrine basin include slide and slump deposits, sandy and muddy debris flow deposits, high and low density turbidity- current deposits, and the common hybrid event beds. Three types of hybrid event beds are identified including sandwich structure, bipartite structure, and banded structure. The bipartite structured hybrid event beds can further subdivided based on the thickness difference between the upper and lower division. Sandwich structured hybrid event beds are mainly caused by flow erosion or liquefaction and located in the proximity of hybrid event beds. Bipartite structured and banded structured hybrid event beds, which are located in the distal part of the hybrid event beds, are mainly attributed to flow deceleration and expansion, and differential settling of detrital grains in a muddy debris flow. The vertical stacking of different beds with the same internal depositional unit composition in the core is a reliable identification mark for hybrid event beds. A lack of knowledge of the formation processes of these hybrid event beds may lead to a misunderstanding of the depositional processes. The development of hybrid event beds adds to the depositional heterogeneity of gravity- flow deposits, which is bad for conventional oil and gas preservation. However, the fine- grained deposits caused by hybrid event beds are good lithofacies associations, which is the sweet spot for unconventional oil and gas development.