Objective: This study focus on determining the lamina shape requirement of flaky tobacco in slim cigarettes. Methods: Six characterization methods of lamina shape were systematically developed by image analysis technique, and the most suitable characterization method of leaf blade shape was determined by the conformance of lamina shape coefficient and visual decision. The lamina shape coefficient database was established by using flaky tobacco from the regional processing center of China Tobacco Jiangsu Industrial Co., Ltd.. Simulation Study on the requirement of lamina shape was conducted based on simulation cutting model, and 114 samples were prepared to discuss the requirement of lamina shape in the laboratory. Results: The results were showed as follows: ① The "Roundness Rate" was the most suitable characterization method of lamina shape. ② There was the largest broken filament rate when the lamina shape coefficient was less than 0.35. ③ When the lamina shape coefficient was greater than 0.428, the broken filament rate was basically under 2%. Conclusion: It is recommended that the lamina shape coefficient of slim cigarettes should be greater than 0.428.