99% of the hydrocarbon resources have been discovered within the sedimentary rocks or erupted volcanic rocks of hydrocarbon bearing basins in the world, only less than 1% of hydrocarbon resources distributed within metamorphosed rocks of buried hill, and the buried depth is no more than 150m generally. The depth of hydrocarbon accumulated in metamorphosed rocks is over 500m from the surface of buried hill has not yet been reported until now. In 2005, Liaohe Petroleum Co., Ltd. of CNPC discovered a large oilfield in the gneiss and mixed amphibolite buried 0~1600m below sedimentary rock of Liaohe Faultdepression of Bohai Bay basin, the hydrocarbon reserve is more than 30 million ton,which indicates a good hydrocarbon exploration prospect in the similar metamorphosed rocks of buried hill with the central uplift belt of Liaohe Faultdepression. The hydrocarbon resources potential in metamorphosed rocks of buried hill in Bohai Bay basin is need to be reevaluated and understood, the hydrocarbon exploration area is much greater than we have ever imagined in the world.