In this work, undoped Mg2TiO4 thin films were fabricated on p-type Si(111) substrates by the sol-gel method, and the red photoluminescence (PL) of the films is introduced and discussed. According to the experimental results, the red emission appears when the films have been thermally treated at higher temperatures, which have a long range and well-organized crystalline arrangement. Furthermore, to have better realization of the red emission mechanism of Mg2TiO4 films, the optical band gap of Mg2TiO4 (E-g(Mg2TiO4)) was estimated at similar to 3.7eV; furthermore, 325nm (corresponding energy, h=3.82eV>E-g(Mg2TiO4)) and 633nm (corresponding energy, h=1.96eV