Abstract: The physico-chemical properties of heavy oils originating from the continental deposits are high viscosity, low sulphur and trace elements content, high non-hydrocarbon and asphaltene content, and low saturated hydrocarbon contents. The gas chromatograms of their saturated fractions exhibit high concentrations of iso-and cyclo-alkanes, and bicyclic sesquiterpane, tricyclic diterpane, rearranged steranes, and gamma-cerane in the terpene and sterane series have a stronger resistance to biodegradation than other biomarker compounds. The formation of heavy oil reservoirs is chiefly controlled by late uplifting of the basin, biodegradation, water-washing, and free oxygen oxidizing. In terms of their genesis, the heavy oil reservoirs can be divided into four types: the weathered-eroded, the marginal oxidized, the secondary migration, and the bottom water thickening. Having a close relationship with normal oil reservoirs, heavy oil reservoirs are mainly distributed longitudinally at the stratigraphically or stracturaliy higher parts, they all buried at a deph less than 2000 meters, and most of them are distributed regionally on the marginal parts of the basin and depression.