Abstract: The porosity development in the hydrocarbon reservoirs of the Bazhou depression,Minhe Basin is treated by means of casting thin sections, scanning electronic microscopy and physical properties of the selected rock samples. Six types and four assemblages of porosity are discriminated for the Cretaceous to Middle-Upper Jurassic hydrocarbon reservoirs in the Bazhou depression.Porosity development may exert an important effect on the physical properties of the hydrocarbon reservoirs in the study area.