Sequential adsorption process of polyelectrolyte and surface sol-gel process was used to deposit on the substrate as the fabrication of ultra-thin films for the: wet process method. The film thickness was precisely controlled using the automatic dipping machine that we developed. Self-assembled film of polyelectrolytes and titanium oxide/polymer composite gel film was sequentially deposited on the polystyrene substrate. The cross-sectional organic/inorganic heterostructure was observed by TEM. It was found that the inorganic layer was homogeneous and flat by the effect of the affinity between the deposited layer and solutions. It was also found that the organic layer was homogeneous and flat when using strong polyelectrolyte.