Abstract: In the preparation of the biofuel or biochemical process, reducing the oxygen content of the feedstock and improving hydrogen carbon ratio are very important. The hydrodeoxygenation is the key to this process. With the expect to provide a reference for finding a highly efficient, green, economic and sustainable catalytic system that can convert biomass into biofuel, this paper focused on the elementary reactions of hydrodeoxygenation and reviewed the development of hydrodeoxygenation reaction according to the differences of oxygen-contained compounds' structure and catalytic systems.