Part of results of research on satellite heat control under the Harvest Project of the National 973 Program is reported.In accordance with the “minimized nucleus” requirement of the satellite,the thermal conductivity of the dielectric FCC argon-crystal nano-film in the normal direction is predicted using the equilibrium molecular dynamic (EMD) and non-equilibrium molecular dynamic (NEMD) methods. The calculated results are compared with the experimental value of the bulk cryastal.Our calculation shows that the thermal conductivity of the thin films is much lower than that of its bulk conterpart,and the size-effect is significant;it increses nearly linearly with increasing thickness in the thickness range of 2.124—5.310nm.