Using starch and powder of potato as materials, effects of 60Coγ irradiation on appearance of starch and the efficiency of saccharification were researched. The results showed that some reticulate flaws emerged in the surface of the starch irradiated by 60Coγ. With the irradiation dosage increased, the reticulate flaws increased. The content of reducing sugar and total soluble sugar in both starch and powder obviously increased along with the increase of irradiation dosage ranged from 50 to 1 200 kGy. The saccharification efficiency of Atlantic and Hunan Potato No.1 had obvious differences when treated by low dose irradiation. But the efficiency performed the similar trends along with the increase of irradiation dose. Furthermore, the saccharification efficiency reached the highest value after the treatment with 1 200 kGy irradiation.