Abstract: During the early Cham brian,here were well-developed lower plants hydrobios and animals group-rich;and deposited black carbonic and muddy shale and carboid whichis one of the best formations containing source rock. Moreover,there is also well-developed another source rock rich-comprising dark limestone. The total volume of the Cambrian source rock in Yangtze region is evaluated to beat least 4000×10⁴km³,and the abundance of organic source rock is much high.Although the thermal evolution of the source rock is generally great,belonging to the mature or over-mature,it still has a better potential producing hydrocarbon If there is a better preservative condition,the Cambrian formation in Yangtze rigion is a better prospective area,and according to the combining analysis for the petroleum geological condition,the middle and lower reaches of the Yangtze river is best exploratory prospective area.