Abstract: Based on outcrop observation and drilling data analysis,it is carried out that the research on the sedimentology and palaeogeography of the Cambrian and Ordovician in the east of Bachu uplift and southeast of Awati depression.During the period of Cambrian-Ordovician,the sedimentary environments developed from deep to shallow water,then to deep water again.The study area was a deep-sea trough in the early stage of early Cambrian,and then evolved to a restricted platform and evaporated platform from middle-late stage of early Cambrian to middle Cambrian.From late Cambrian to middle Ordovician,the sea level began to raise gradually,the area was dominated by an open platform,and evolved to a platform marginal slope in the middle stage of late Ordovician.