Abstract
This research designed a set of experimental instruments (TDMI) to measure the thermal diffusivity α of the material. TDMI is calibrated by pure substance such as copper, tin, lead, Aluminium 6061 etc., after done the calibration, the thermal conductivity of heat pipe graphite sheet and vapour chamber also be measured. The repeatability error in this experiment, are within 5%. Compared with the thermal diffusivity data of those the pure substance from handbook while for the accurate relative error were within 10% as well.