The invention relates to a process for producing a stable solution containing Anatase titanium oxide intended to be deposited on a substrate in order to obtain a transparent photo-catalytic coating. Such a process includes the preparation of an initial stabilized peptized solution including a titanium precursor material, an organic solvent, an acid agent, the mixing of said initial solution with a large amount of water, the pH of the obtained intermediate solution being less then 3, subjecting said intermediate solution and its dispersion to a heat-treatment, the exchange of water by an organic solvent with low surface tension to obtain a final solution that is finally dispersed. The invention particularly allows to coat thermally sensitive and/or transparent substrates with photo-catalytic films of high optical quality.