Abstract: Studing the differences of potato growth and yield formation under different irrigation quantity with drip irrigation, the relationship of potato moisture absorption and yield formation and regulatory mechanism were theoretically verified, to determine the potato irrigation system of water saving and high yield.With the increase of irrigation quantity, plant height, stem diameter, the dry weight of ground organs and tuber yield were unimodal curve change with drip irrigation under membrane. Yield was the highest when irrigation quantity was 1 650 m3/hm2, which was the most suitable irrigation quantity. A moderate amount of irrigation can promote the plant growth and was beneficial to delay the plant senescence.