Abstract: The paper introduced a test method of thermal diffusivity of loose coal based on unsteady-state heat conduction multiplication-method, designed a measurement system for thermal diffusivity of loose coal,expounded working principle,composing structure and design of treatment software of the(system. Finally, it analyzed error of the system. The system realized automatic data collection and processing, and solved the problem that measurement is excessive caused by experimental device heat loss. It satisfied for test requirements.