Hydrocarbon-bearing reservoirs found in buried hills are important targets with abundant reserves in Eastern China，but the reservoir space in buried hills is very complicated because of lithology changing，fault activity and fluid erosion. After observing cores from Chengdao buried hills composed of Ordovician carbonates，it is found that fractured carbonates（fracture density<10 fractures/m），cataclasites（fracture density>10 fractures/m）and breccias（2-8 cm gravels）are formed because of fault activity，among which breccias and cataclasites are clearly dissolved and rich in oil，but the fractured carbonates and ordinary carbonates are poor in oil. According to well logging and seismic interpretation，five assembles（fault frature zones）of fractured carbonates，cataclasites，and breccias are proposed，and the distribution of a new-type of reservoir body that mainly composed of breccias and cataclasites in buried hills is predicted. According to rock-mineral and geochemistry analysis，the dissolution of minerals with ground waters and thermal fluids flowing through the faults in the breccias and cataclasites is clarified，and it is believed that ground water plays a dominant role in the formation of reservoirs in fault frature zones during hydrocarbon accumulation. The prediction and evaluation of this new type of reservoir body is helpful to predict reservoir spaces and oil distributions in complicated buried hills，as well as to efficiently produce oil from the buried hills.