In the field of geophysical exploration, great attention has been paid to the utilization of the streaming potential characteristics in reservoir rock to describe the flow characteristics of the reservoir. According to the electrical double-layer model and the electrochemical theory, the authors derived the coupling relationships between flow field, ion field and current field based on the capillary model. The influences of pore structure parameters on the coupling coefficient of streaming potential were obtained by numerical simulation. The results show that, when the influence of the concentration polarization effect on streaming potential is considered, the absolute value of coupling coefficient of streaming potential increases with the increasing solution concentration, cation exchange capacity, porosity and permeability. In addition, the concentration difference polarization amplifies the streaming potential.