Abstract: In order to evaluate suitable morphology for cut tobacco strands in demi-slim cigarettes, the morphology of cut tobacco strands was characterized by the characteristic length. The relationships of the characteristic length with the quality indexes and consistency of finished demi-slim cigarettes were analyzed with tobacco morphology control technology. The results showed that: 1) When the characteristic length of tobacco strands (before rolling) was in the range of 2.35-2.85 mm, the consistency of physical indexes of the cigarettes was better. 2) The loose end percentage, density standard deviation and density distribution consistency coefficient η of the cigarettes all decreased first and then increased with the reduction of the characteristic length. 3) When the characteristic length of tobacco strands (before rolling) was in the range of 2.35-2.80 mm, loss of tobacco from the end of cigarette and combustion cone falling propensity were lower, and the distribution consistency of dynamic draw resistance fluctuated to a certain degree. 4) Considering the differences between tobacco blends, the consistencies of physical indexes and density of demi-slim cigarettes were improved and the loose end percentage, combustion cone falling propensity and loss of tobacco from the end of cigarette were lower when the characteristic length of tobacco strands (before rolling) was in the range of 2.35-2.85 mm and the frequency of roll screen was between 37-47 Hz.