Abstract: Baxian Sag is one of the main oil-rich sags in Jizhong Depression. The multi phase Paleogene sandstone of fan delta and braided delta superimposed in succession in deep zones(> 3 500 m). The composition and texture of sandstone are high mature,and the reservoir physical properties are relatively good,which provides better reservoir conditions for deep hydrocarbon accumulation. In order to understand the distribution characteristics of deep reservoirs and their controlling factors,the study was carried out by the conventional evaluation methods, oil occurrence method and porosity-permeability crossplot method,combined with the data of drilling,logging and mud logging. The effective sandstone reservoirs are controlled by five factors,such as parent rock type,sedimentary facies belt,diagenetic facies belt,undercompaction and early hydrocarbon charging. The Paleogene deep reservoirs in Baxian Sag have geological features such as the abundant-feldsparparent rock, the braided/fan delta front,the strong dissolution-weak cementation diagenetic facies belt,the abnormal pressure belt and early hydrocarbon charging. They are favorable for effective reservoirs at least at depth of 5 500 m. The deep exploration of Paleogene lithologic reservoirs is prospective in Baxian Sag.