A series of technical data for the preparation of ferroelectric thin film PLZT by RF sputtering at substrate temperatures lower than 400°C with subsequent annealing is described. Films with dielectric and optical properties of considerable quality have been obtained under certain conditions. Parametric changes in the dielectric, optical and pyroelectric properties according to sputtering, annealing conditions and film thickness have also been clarified. The dielectric properties depend heavily on film thickness. Well-annealed thick films have dielectric constants nearly equal to those of ceramics. Discussion on the thickness dependence of dielectric properties and on the effects of the packing density of PLZT and other preparation conditions is made.