The use of electrophoretic deposition (EPD) has been investigated into the polyelectrolyte multilayer nanocomposites constructed with weak polyelectrolytes such as linear polyethyleneimine (LPEI) and poly acrylic acid (PAA) and inorganic clay particles, montmorillonite (MMT), comparing the growth rate, clay composition, surface/internal structures, and mechanical properties. An introduction of electric field was shown to enhance the exponential deposition rate of polyelectrolytes and MMT particles, attaining about 1μm thick film at 10 quadlayers (QLs), while the same number of PNCs in the absence of electric field had 150 nm in thickness. The brick wall nanostructure created by highly oriented clays and polymeric mortar with an electric field applied improved the mechanical properties such as Young's modulus (45 GPa) and tensile strength (75 MPa) at 20 QL-PNCs, which is 40 and 30 times as high as the same thickness of 50 QL without applied electric field, respectively.