Tritium diffusion and permeation in construct materials is one of the most important problems in fusion material research. For the tritium concentration evaluation within each sub-system of the fuel cycle of ITER, a finite volume computer program was developed for diffusion analysis of hydrogen isotopes in composite materials. The program calculates hydrogen isotope concentration distributions through composite materials such as tritium permeation barriers as function of the applied boundary conditions. The program can simulate hydrogen isotopes diffusion through single materials and composite materials in one-dimensional and can also make the output visualization. We look forward to making some comparison calculation for the present calculation with TMAP. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.