A comprehensive characterization of basic heterogeneous cation-exchange MK-40 and Ralex CMH membranes and composite membranes with polyaniline based on them was performed, including the determination of conductivity and diffusion permeability, measurement of current–voltage curves in solutions of sodium, calcium, magnesium chlorides and hydrochloric acid, distribution curves of water binding energy and effective pore radii, as well as an assessment of the transport-structural parameters of microheterogeneous model. The time of polyaniline synthesis on the surface of cation-exchange membranes by successive diffusion of an oxidizing agent and monomer solution through the membrane into water was determined. Samples with an anisotropic structure and asymmetric electrotransport properties were obtained. Based on the analysis of the electrotransport properties, structure characteristics and model transport-structural parameters of membranes in solutions of singly and doubly charged ions, the obtained materials were defined as promising for use in the processes of electrodialysis desalination of multicomponent solutions.