Abstract: The physical properties, diagenesis and porosity evolution of the Palaeogene-Neogene hydrocarbon reservoirs in the Sikeshu depression, Junggar Basin, Xinjiang are discussed on the basis of well logs, thin section examination and mercury-injection curves. The Palaeogene-Neogene hydrocarbon reservoirs in the Sikeshu depression are characterized by medium-to fine-grained sandstones, abundant primary porosity, and B substage of the early diagenesis and the A substage in local places. These hydrocarbon reservoirs belong to the moderate mesoporosity and mesopermeability reservoirs, and thus have good reservoir potential.