A novel electrical field assisted membrane module consisting of an array of microchannel units, each microchannel unit comprised of a cylindrical pore and a charged ion- selective membrane layer, is analyzed theoretically. The governing equations for the flow and the electrical fields are solved analytically under the Debye- Huckel condition and the influences of the key parameters on the flow behavior of the system under consideration are investigated through numerical simulation. We show that for a fixed microchannel radius, the volumetric flow rate through a microchannel unit has a maximal value as the radius of the cylindrical pore varies. This maximum is independent of both the strength of the applied field and the density of the fixed charges in the membrane layer, but varies with the permittivity of the membrane layer.