In this paper, lattice Boltzmann method is used to simulate the phonon heat transport in NaCl@Al2O3 mesoporous composite material. Based on the Debye model, temperature coupling method is first proposed in the thermal simulation of mesoporous composite material, to calculate the effective thermal conductivity of mesoporous composite material with pores of various interface condition coefficient value, pore size, porositiy, shape and arrangement. Studies show that for the same porosity, the estimated thermal conductivity increases with increasing the value of diameter, showing the scale effect; for the same diameter, the estimated thermal conductivity decreases with increasing the value of porosity; for the same porosity and diameter, the estimated thermal conductivity decreases with increasing the value of interface condition coefficient p; porous shape and arrangement will affect thermal conductivity value, and the influences greatly increase with increasing the value of p.