A series of composites based on the perfluorinated MF-4SK membrane and polyaniline was obtained under electrodiffusion of monomer and oxidizer. Aniline was used as monomer and potassium dichromate as oxidizer. Chronopotentiometry was proposed as the method of monitoring the formation of polyaniline in the near-surface layer of the membrane. The electronic absorption spectra of the composites and optical microphotographs of the surfaces were obtained right after membrane modification. A combined interpretation of results revealed the following stages: the accumulation of monomer in the reaction space accompanied by the onset of polymerization, the polymerization with a subsequent increase in rate, and the formation of modifier layer on the membrane surface. The polarization behavior of composite membranes was studied using voltammetry. It was shown that the presence of two limiting currents (pseudo-limiting and limiting) on the current-voltage curves when the composite was oriented with a polyaniline layer to the counterion flow but only for membranes obtained at synthesis times more than 35 min. Also for these composite membranes, no plateau of the limiting current on the current-voltage curve was observed in the case of reverse membrane orientation. But at the same time, the fluctuations of potential drop on the current-voltage curve indicated the overlimiting state of electromembrane system. A correlation between the shape of the chronopotentiogram recorded during membrane modification and the polarization behavior of the obtained composites was found.