The secondary pores and fractures constitute the major storage space and percolation path in muddy gravels in Kulongshan oilfield, Jiuquan Basin. A comprehensive evaluation on categories, types, scales, the attribute of parameters and formation mechanism shows that the secondary pores and corrosion fractures increase the permeability of reservoir, and the reservoir porosity. The nonhomogeneity of diagenesis and tectogenesis make the characteristic of physical property different obviously. The different parts of turbidities fan and the change of gravel size from a facies analysis are the main factors controlling the types and combinations of pores and fractures. The chief principle of improving the reservoir quality in the diagenetic stage is corrosion, including the mutual replacement and dissolution in muddy gravel, unstable debris particles of different (optional) solution. The structural evolution of reservoir indicates that the NW-striking reverse fault, which was formed by Himalayan orogenics, controls the formation of reservoir noticeably, and NE-striking adjustment fault leads to a different growth in fracture system.