The current efficiency eta of a planar membrane bearing nonuniformly distributed fixed charges is analyzed theoretically. In particular, the effect of the convective boundary layer near the outer boundary of the membrane is discussed, Two types of fixed charge distribution are considered : a class of linear distribution and a class of exponential distribution. We show that, if the flow velocity in the membrane phase is small, increasing the inhomogeneity of fixed charge distribution is capable of raising eta. However, if it is appreciable, the reverse is true. If a boundary is present, eta decreases with the increase in current density the reverse is true if it is absent. The former is due to the fact that the degree of concentration polarization in the boundary layer increases with current density, Although the existence of a boundary layer has the effect of reducing eta, the convective flow of fluid perpendicular to membrane has a positive effect on eta. If a boundary layer is absent and the fixed charges are distributed homogeneously, eta is independent of current density I; if the boundary layer is present, eta will vary with I.