High quality lead titanate thin films were fabricated by spin coating on a silicon substrate. The resulting dried gel layers were uniform in thickness through 2$ imes$2 $ extrm{cm}^2$ area, and polycrystalline perovskite structures developed almost crack free with a heat treatment above 50$0^{circ}C$ in films with thickness above 360 nm. Metastable pyrochlore structures were observed in films with thickness of 160 nm when heat treated at 500 and $600^{circ}C$, but these structure did not appear in films with thickness of 360 nm. The thickness dependence in crystal structure of films was studied. by varying the substrate condition and analyzing the interface between the film and substrate. In native oxide films on silicon stbstrates, amorphous dried gel layers were heterogeneously nucleated. Metastable cubic pyrochlore structure could be crystallized in amorphous native oxide.