Abstract: Most of the phase change material when they convert from the solid phase to the liquid phase，absorb the latent heat of the phase change material，and the volume of the phase change material expands；when they convert from the liquid phase to the solid phase，release latent heat of the phase change material，and the volume of the phase change material reduce.By use of the characteristic of the volume of the phase change material variation with the phase transition，a certain amount of the phase change material closed in a sealed container，the phase transition of the phase change materials with the variation of the ambient temperature，the stress which is produced due to the volume changes during the phase transformation，provides drive force for moving mechanism requires some tiny displacement.Finally，the property of the phase change materials is applied for micro drive in spacecraft with example.