Abstract: In order to solve the problem of permeability evaluation for low-resistivity and low-permeability reservoirs in the Pearl River Estuary Basin in the western South China Sea, this paper made a detailed investigation on the origin of the low-resistivity and low-permeability reservoirs both at home and abroad, and deeply analyzed the influencing factors on reservoir permeability. The results show that the radius of pore throat is the main reason for the great difference in permeability from reservoir to reservoir. Based on core data, reservoirs are divided into six types by FZI method in this case. The permeability of low-resistivity and low-permeability reservoirs is calculated by establishing fine permeability models for each type of flow units. The results prove that the flow unit permeability model can effectively improve the accuracy of permeability calculation, and this method has been widely used in the Western South China Sea.