Tobacco leaves are mostly harvested manually, which consumes a lot of time and labor. To develop the tobacco leaves harvester, the harvesting mechanism which is the core component of the harvester was studied. Firstly, the mechanical harvesting model of tobacco leaves was established based on ADAMS software. The operating parameters that affect the mechanical harvesting of tobacco leaves are the rotation speed of the harvesting tool, the feeding speed of the harvesting tool, and the installation angle of the harvesting tool. To increase the harvesting rate and reduce the breakage rate, these three operating parameters were used as variables for simulation experiments. Through the analysis of the simulation experiments, nine groups of appropriate operating parameters were obtained, which can be used as guiding parameters for actual harvesting work. Secondly, the tobacco leaves harvesting test-bed was designed and manufactured to verify the simulation results. Based on the simulation results, orthogonal experiments were designed. In addition, two groups of harvesting tools with different hardness were used for experiments. The orthogonal experiments results revealed the effects of the rotation speed, the feeding speed, the installation angle, and the hardness of the harvesting tool on the harvesting rate and the breakage rate. Finally, the optimal combination of operating parameters was obtained, which is 0.9 m·s-1, 175 r·min-1, 8º. When the hardness of the harvesting tool is 56 HA, the mechanical harvesting of tobacco leaves can reach the harvesting rate of 90% and the breakage rate of 14%.