The self-assembled mono- and multilayers (SAMs) of poly(diallyldimethylammonium chloride) (PDMA), poly(sodium styrenesulfonate) (PSS) and poly(acrylic acid) (PAA) were used to modify the substrate surfaces for depositing polypyrrole (PPy) films prepared by in situ polymerization. It was found that the PSS layers could not only lead to thicker and denser PPy films, but also improved the uniformity of the films. Modifying substrates with polyelectrolyte self-assembled layers is a convenient and practical way to improve the quality of some functional films.