The work aims to carry out three-dimensional numerical analysis on the internal flow field in the cigarette adsorption channel with CFD method aiming at the poor stability of cigarette transfer and packaging. The flow characteristics of key parts were studied, the flow velocity, pressure distribution and turbulent dissipation were analyzed, and the structural improvement scheme was proposed. The distribution of flow field pressure and velocity was unreasonable at the connection position between the cigarette adsorption port and the fan, the turbulent kinetic energy at the corner was large, and the pressure loss between the cigarette adsorption port and the fan was 5 268 Pa. A large adverse pressure gradient was observed in the fan pipe. Thus, airflow vortex was caused and pressure loss was 14 000 Pa, which was higher than the industrial demand. In the optimized model, when the fan pipe contained two corners, the pressure loss was reduced by 7 000 Pa and the cigarette adsorption effect was increased by 350%. When the fan pipe contained a corner, the pressure loss was reduced by 6 200 Pa, the cigarette adsorption effect was increased by 390%, and the rationality of field flow distribution channel was improved. Based on the simulation results, the connection mode between the fan and the outlet pipe is optimized, and the flow field analysis can provide technical support for the optimization design of the cigarette adsorption unit.