A novel wet process to synthesize metal oxide thin films has been developed. The process is called the Liquid-Phase Deposition (LPD) method. In this method, metal oxide or hydroxide thin films are formed on the substrate through the ligand-exchanging (hydrolysis) equilibrium reaction of metal-fluoro complex species and the F− consumption reaction of a F− scavenger. The LPD method is a unique soft solution process, and is performed by very simple procedures. In this paper, we develop a method of preparing composite oxide thin films, Pt-dispersed titanium oxide, and iron-nickel binary oxide thin films.