The invention discloses a potato biscuit and preparation technology thereof, wherein the biscuit comprises 45-55% of potato starch, 10-15% of potato whole powder, 10-15% of white sugar, 10-15% of shortening, 5-10% of refined plant oil, 3-7% of glucose syrup, 2-5% of ammonium bicarbonate, 1-3% of sodium bicarbonate, 0.5-1% of salt, 0.1-0.3% of flavoring composition, and the balance is water. The biscuit has no flour; the potato starch is used as the main raw material; and the problem of the local flavor influenced by a traditional biscuit that has a heavy batter taste is solved. At the same time, the potato has a high nutrition value; the digestible ingredients are high and can be absorbed by human body easily; the quality is close to animal protein; the potato is rich in amino acid; and the nutrition value of the biscuit is raised, therefore, the problem of low economic value because the potato is mainly used as a fresh food in traditional agriculture is solved. By employing a traditional wheat flour biscuit production apparatus and technology, the biscuit prepared has a totally different mouthfeel; the local flavor is more characteristic; demand for more tastes can be satisfied; at the same time, the yield through the preparation technology is large; and the production efficiency is high.