Abstract: Lunar detection is the beginning of the deep space detection. The energy for the satellite running around the moon is provided by the power system of solar arrays. The lunar orbital environment has the direct effects on the operations of the solar arrays. The characteristics of the surface of the moon and of the lunar orbit have been analyzed. The research object is a rigid solar array in polar lunar orbit. The method to determine the external heat fluxes received by solar array has been shown detailedly on the basis of fully considering the packing factor and the solar cell conversion efficiency. The process of heat transfer in solar array is treated as 3-D anisotropic transient heat conduction problem without internal heat source. Grid division has been made in the solar array and the fully implicit discrete equations have been acquired. The numerical simulation of solar array in polar lunar orbit has been made and the periodic distributions of the external heat fluxes and the temperature of solar array have been obtained. Comparison between the numerical results in earth orbit and that in lunar orbit shows the characteristics of the periodic distribution for thermal parameters of the solar array in lunar orbit, which will provide powerful references for the design of the solar array and the whole lunar satellite.