Abstract: The arithmetically averaged melocular weights of certain heavy crude oils of continental facies and their components were determined using VPO method, which provided important parameters of chemical structure for hydrocarbons. The results show that the arithmetically averaged melocular weights of continental facies heavy crude oils in China range approximately from 480.1-686.2. The arithmetically averaged melocular weights of their components are as follows. 385.2-398.6 for saturated hydrocarbons; 362.5-464.7 for aromatics; 755.7-1321.7 for resin and 856.7-4043 for asp-haltene. The melocular weights are closely dependent on the maturity specific density and group composition of crude oils.