Abstract: The structure of porous materials was reconstructed by using a Monte-Carlo method. It is verified that the reconstructed model has the fractal characteristics of self-similarity and scale-invariance. The reconstructed structure of porous materials was first meshed, and solid and fluid phases of the grids were identified by the binary theory. Then a series-parallel connection array model was established for the real heat transfer process. Finally a method of calculating the thermal conductivity of homogeneous and non-homogeneous porous materials, namely, the binary array method, was proposed. Closed-cell foam aluminum and alumina-silicate refractory fiber materials were taken as examples, and the binary array method was used to calculate their thermal conductivities. The calculated values fit well with experimental results respectively, proving the correctness and universality of the binary array method.