The growth and biochemical effects of different plant hormones on virusfree potato seedlings were studied in hope of providing theoretic basis for Potato Microtuber production.The results of the study showed that the plant hormones (1)greatly improved the root growth vigor and potentials of the potato seedlings and increased the root protein content of the seedlings;(2)Evidently increased the net photosynthetic rate,dry matter,chlorophyll content as well as photosynthate accumulation of the seedlings;(3)Increased evidently the activities of SOD,POD,CAT and the free amino acid content and decreased the content of MDA;(4)Significantly promoted the potato seedlings which were better to have a minituber number and yield per plant.Thereinto,with NAA at 100 mg/L,IBA at 50 mg/L and boric acid at 17.5 mg/L,the photosynthetic pigment content,net photosynthetic rate,protective enzyme activities,free amino acid content of the seedlings were the most favorable and the minituber number and yield per plant appeared the highest as well.