The invention relates to the research field of composite material property, in particular to a heterogeneous mesoporous composite material thermophysical property calculating method. The method includes the steps of: sample characterization: characterizing the properties of structure and composition of the composite material; thermophysical property testing: conducting thermophysical property testing on the composite material to measure values of thermal conductivity of all samples; theoretical calculation of the thermophysical property: respectively abstracting thermal conductivities of base material and filler of the heterogeneous mesoporous composite material to obtain the effective thermal conductivity by adopting kinetic theory in combination with molecular dynamics simulation, wherein near-field radiation, interface scattering as well as the coupling effect between the base material and the filler are taken into account; verification: in combination with the test result, further completing a relevant diathermanous mathematical model of the heterogeneous mesoporous composite material under nanometer pore size. Compared with the prior art, the heterogeneous mesoporous composite material thermophysical property calculating method disclosed by the invention solves the problem of solving the physical property parameters of the composite material under nanometer pore size, the accuracy of the thermophysical property is improved and material design is optimized.