As the complexity of sandstone pore-throat structure is an important factor affecting its permeability and the permeability is crucial to evaluating high-quality reservoirs，it is vital to quantitatively characterize the complexity of sandstone pore-throat structure. Therefore，this paper takes the sandstone of Shahejie Formation in Dongying Sag as an example.On the basis of the thin section identification，XRD，and MICP test，it introduces the pore throat volume fractal dimension，tortuosity，and tortuosity fractal dimension to quantitatively describe the pore throat structure of sandstone and explore their petrological factors. In addition，it systematically analyzes the relationship of volume fractal dimension，tortuosity，and tortuosity fractal dimension with permeability. The results show that the complexity of pore throat structure and permeability of sandstone in Shahejie Formation of Dongying Sag are greatly affected by sedimentary microfacies. The average pore throat diameter is an important factor to control the complexity of pore throat structure，and the complexity of pore throat structure （the volume fractal dimension，the tortuosity，and the tortuosity fractal dimension）is a key factor affecting the permeability of sandstone.