The invention relates to a process method for reducing the content of tobacco stem pectin at high temperature and high pressure, and relates to the field of tobacco processing. The process comprises the steps of carrying out tobacco stem high-temperature high-pressure expansion, stem washing and pectin dissolving out, spiral squeezing dehydration, stem pressing, stem cutting, feeding and baking, and final obtaining of a cut stem finished product. According to the method, the hard tobacco stems are expanded through high temperature and high pressure, so that the tissue structure is loose; and under the action of high temperature and high pressure, long-chain pectin in tobacco stems is broken, so that the dissolution rate of the pectin is improved. By virtue of high-temperature and high-pressure expansion, and water washing and squeezing, the pectin content in tobacco stems is reduced, the quality of cut stems is improved, the irritation and pungent feeling are reduced, the use ratio ofthe cut stems in cigarettes is increased, and particularly, due to the reduction of the pectin content of the cut stems, the knife sticking phenomenon of tobacco stems in the stem sticking process andthe shredding process of the follow-up tobacco stem pressing process is relieved, and the processing quality and the processing efficiency of the cut stems are improved. The method disclosed by the invention is simple in process, strong in operability and obvious in effect, and has a relatively high application prospect.