A Monte Carlo simulation method of light scattering in nanocrystalline films based on solutions of Maxwell＇s equations is proposed. A nanocrystalline film is assumed to be superposition of randomly distributed nanoparticles and deviation of the nanocrystalline film from the randomness, Since a scattering field of the randomly and densely distributed nanoparticles can be neglected, a scattering held of the nanocrystalline film results in a sum of scattering fields of the deviant parts in the nanocrystalline film. In the method, configurations of the deviant parts are simulated with a random function of a computer language. A simulation converges in small number of the configuration patterns. The simulation theoretically demonstrates that almost all of the incident light to the nanocrystalline films in the photoelectrochemical solar cells penetrate without scattering. (C) 2000 Elsevier Science B.V. All rights reserved.