Based on a microscope capillary model,a mathematical model for induced polarization of reservoir rock is obtained.Influences of concentration difference polarization and electric double-layer deformation on induced polarizability are studied numerically.It shows that induced polarization is governed by ion concentration difference polarization in capillary.Electric double-layer deformation has greater influence on total polarizability.Speed of charging and discharging in induced polarization depends mainly on cation exchange capacity and pore structure of rock.