This letter describes a new method to prepare Fe3O4 thin films on glass substrates from aqueous solutions kept in a temperature range from 333 to 343 K. The process includes the deposition of precursor thin films, alpha-FeOOH, by oxidation of Fe2+ ion in aqueous solutions, and the conversion of the precursor to Fe3O4 in another solution. The film thickness, microstructure and magnetic properties of the resultant Fe3O4 thin films were characterized.