Abstract: While keeping the proportion of long strands (>2.5mm) above 80%, the proportion of small strands (<1.00mm) below 3%, the filling power and purity ≥ 4.2cm³/g and ≥ 99%, respectively, the effects of size distribution of cut tobacco on the loose end ratio of cigarette and the proportion of long strands and the filling power of cut tobacco in break-out rod were studied by controlling individual cigarette weight and the speed of cigarette maker.The results showed that the loose end ratio was mainly influenced by the change rate of the proportion of long strands, when the latter increased by 1%, the former decreased by 0.2%, the proportion of long strands of cut tobacco in break-out rod increased by 0.92%, the proportion of small strands decreased by 0.12%, and the filling power increased by 1.1%.However, the loose end ratio was affected to a lesser extent by the structure and filling power of cut tobacco.