Membrane extraction process for tobacco leaching liquor

The invention relates to a membrane extraction process for a tobacco leaching liquor, which comprises the following steps: 1) soaking the waste of tobacco containing tobacco scraps left in the production of tobacco and discarded tobacco with water to obtain a tobacco soak solution; 2) separating solid impurities from the tobacco soak solution by a vibration screen to obtain tobacco leaching liquor; 3) filtering the tobacco leaching liquor with a tubular ultra-filtration membrane to obtain tubular ultra-filtration dialysate; 4) passing the tubular ultra-filtration dialysate through a rolled nanofiltration membrane to obtain a nanofiltration concentrated solution; 5) evaporating the nanofiltration concentrated solution to obtain tobacco extract; 6) evaporating the dialysate of the rolled nanofiltration membrane by reverse osmosis concentration. According to the membrane extraction process for the tobacco leaching liquor, solid impurities, some large protein pectin and the like in the tobacco leaching liquor can be retained by removing the impurities by the tubular ultra-filtration membrane, substances which can affect the tobacco leaching liquor are completely removed from the obtained tubular ultra-filtration dialysate, and the mouthfeel and quality of the smoke extract are improved.