Weihe Basin is a Cenozoic basin,located in the transitional area of the southern margin of the Ordos block and the Qinling orogenic belt. The Paleogene-Neogene successions are of several kilometers in thickness,and of various sedimentary types. Based on drilling data and fieldwork observation and measurement,the stratigraphy,sedimentology and lithofacies palaeogeography of the Weihe Basin were studied. The stratigraphic units of the Cenozoic in Weihe Basin were redefined. According to the sedimentary characteristics,five depositional types were distinguished in Weihe Basin, i.e.,alluvial fan,fluvial,lacustrine,deltaic and eolian deposits. The results suggest that:Due to fault,subsidence and filling during the depositional process,the basin is extremely dissymmetric in profile and has the depocenter locating southerly. The basin is narrower in the west and wider in the east. Alluvial fan is predominant in the marginal area,which gradually transforms into the delta and then the lake towards the center. The Weihe Basin began to deposit since the Eocene. It was uplifted and had a hiatus during the Late Oligocene. During the Miocene,it restarted to deposit in the Lengshuigou Age;as the distribution range of water body gradually expanded,it widely developed lakes in the Koujiacun Age,and reached the maximum sedimentation area up to the Bahe Age. During the Pliocene Youhe Age,it formed two major depositional depressions within the basin,i.e.,the Xi'an Depression and the Gushi Depression; meantime,the eolian deposits firstly appeared at the basin margin. During the Quaternary,the western region of the basin was uplifted,and the distribution range of lakes gradually shrinked. From the Middle Pleistocene to the Holocene,the lakes shrinked into small sags locally.