To make the rapidly developing micro-satellite further smaller and lighter, based on gel polymer lithium-ion battery and high thermal conductivity carbon fiber reinforced epoxy resin composites and polymethacrylimide (PMI) foam, a kind of multifunctional satellite structure-battery (SB) is designed in the paper, and an investigation of its thermal property in certain working environments is carried out by numerical simulation approach. The role of two parameters, longitudinal thermal conductivity of carbon fibers and the heat dissipation area, play in the temperature distribution while the SB is working, is analyzed. The result shows that, enlarging the heat disspation area is an effective way to decrease the maximum temperature of SB and it also implys that by selecting the two parameters carefully, the largest temperature rising of the SB could be considerably lowered, alleviating the burden of satellite thermal control subsystem.