To improve the heat-dissipation regulation capability and thermal environment adaptability of space thermal control subsystem, a micro-expansion type heat switch with micron stroke was designed. The structural components and operating principle of the switch were introduced, and the key thermal properties of heat switch, including OFF resistance, ON resistance and ON/OFF ratio, were evaluated by combination of theory, simulation and experiments. Theoretical thermal properties of heat switch is calculated based on the series-parallel relationship of thermal resistances, the OFF resistance and ON resistance are 301.71 K/W and 1.06 K/W, respectively, the ON/OFF ratio is about 283.6. Transient thermal properties of the OFF/ON process was analyzed by the finite element model, when the heating power of hot end is 18 W, the turn-ON response time and triggering temperature are 340 s and 35.5 ℃, and the ON resistance is about 2.3 K/W. Moreover, in the twice property experiments,the ON resistance and ON/OFF ratio are 1.08 K/W, 279.4 and 1.67 K/W, 180.7 respectively,and experimental data is in agreement with the theoretical calculations well. The experimental results point out that the uncertainty of assembly-regulation process would cause small interval fluctuations of macro thermal properties of the heat switch, The conclusions cloud provide references for structural optimization design, machining refinement and assembly-regulation improvement of subsequent micro-expansion type heat switches.