Abstract: For improving stem's usability in reconstituted tobacco production and raising reconstituted tobacco quality, the pectin in tobacco stem was reduced with pectinase and the reaction conditions were optimized with orthogonal experiments. The results showed that from the point of pectin removal rate, the optimum reaction conditions were:reaction temperature 45℃ for 8 hours, pH of solution 5.8 and 0.2 g of pectinase for every 10 g of tobacco stem. Under such conditions, pectin removal rate was up to 81.02%.