We studied effective drying of cut potato using a vacuum microwave radiation-drying (VMRD) method. Some basic information obtained from this study is. (l) Three typical periods in the drying process (preheating period, constant-rate period, falling-rate period), were also found in the VMRD method. (2) The drying rate of potato in the constant-rate period was as high as the evaporation rate of water under the same condition. (3) Sample temperature at constant rate period was equal to boiling point of water under the operating pressure (4) Critical moisture content was about l00DB%, irrespective of the operating pressure and microwave power. The VMRD method (≦150 Torr, ≦3kW/kg-dry matter) maintained desirable flavor and component of raw potato, compared with other commonly using drying methods, e. g. draft-drying etc.. Moreover, whole potato granules prepared in the VMRD method had advantageous characteristics on　fermentation and puffing. Vacuum microwave radiation-drying method is effective on development of　novel, value-added products.