Thin film of PbI-based layered perovskite having an superlattice Structure, (C22H45NH3)(2)PbI4, Was successfully prepared through successive deposition of docosylammonium. monolayer, which was spread on an aqueous solution containing of PbI2 and methyammonium iodide, by using the Langmuir-Blodgett (LB) technique. The LB film exhibited a sharp and strong exciton absorption around 500 mn which is characteristic of PbI-based layered perovskite. In addition, X-ray diffraction measurement demonstrated that the layer structure with a layer spacing of 3.2 mn was oriented parallel to the film plane.