We tested the thermal resistance of a carbon-fiber-reinforced fuel storage tank by using the simulations and the experiments. A model describing the one-dimensional heat transfer in a composite wall exposed to a flame was developed. As a moving boundary condition, the thickness recession is expressed by the one-step Arrhenius-type decomposition kinetics. The differential equations are solved by the Crank-Nicolson method, the algorithm of which is developed by us. For the experimental verification of the simulation, the well-controlled heat is added to one side of the square specimen taken from a carbon-fiber-wounded epoxy cylinder and the change in mass of the specimen is recorded as time passes. From the comparison of the results of two methodologies, it is hypothesized that the normalized thickness by the initial value should be always equal to the normalized mass by the initial value at a certain time. As a result, the surface recession data obtained by the simulations provide good predictions for those by the experiments.