To solve the problem of high tobacco content and serious tobacco waste caused by poor equipment parameter settings in the tobacco stem shreds air separation process of the existing air separator of tobacco cutting workshop, this paper proposes a computational fluid dynamics (CFD) simulation analysis strategy for the aerodynamic characteristics of particle suspension in the air separator of tobacco cutting workshop. Firstly, in response to the problem that CFD numerical simulation software can only be applied to spherical models and cannot directly simulate the process of tobacco stem shreds selection, the discrete element analysis strategy DEM is introduced for fusion improvement, achieving effective simulation analysis of tobacco stem shreds selection process. Secondly, in response to the existing literature not considering the movement of the cut stem particles in the air separator and neglecting the particle collision during the tobacco stem shreds separation process, which leads to a certain deviation in the analysis data, a collision simulation model considering the radial movement distance between the stem and the floating chamber wall of the air separation device is introduced, which is fed back into the DEM-CFD fusion numerical simulation process to deeply optimize the parameters and improve the recovery efficiency of tobacco consumption. Finally, a domestic cigarette factory brand tobacco stem shreds and sticks were used as the experimental object for simulation analysis, and the optimal separation negative pressure of the air separator of the tobacco cutting workshop was obtained, verifying the effectiveness of the proposed method.