Abstract：To address the insufficient dust control in traditional Long-duct forced and short-duct exhaust ventilation system within fully mechanized excavation faces， the study proposes a novel ventilation and dust removal system incorporating a flow distribution device. Through three-dimensional numerical modeling combined with Fluent simulations and field measurements， the mechanism of airflow field regulation and dust migration control is systematically investigated. The gas-solid coupling process is simulated using a heterogeneous Eulerian multiphase model with Realizable k-ε turbulence modeling， while a mathematical model of flow distribution ratio based on modified Bernoulli equations is established. Five pressure-exhaust ratios (3：2 to 2：3) are comprehensively evaluated through entropy weight method. Results demonstrate that the flow distribution device generates a gradient pressure field with terminal positive pressure and heading negative pressure， creating directional airflow to suppress dust diffusion. The optimized system reduces rear-tunnel dust concentration from 116.5 mg/m3 to 8.3 mg/m3. Under the 5：4 pressure-exhaust ratio (700m3/min supply /560m3/min exhaust)， dust removal efficiency reaches 96.5% with 59.81% reduction at operator position， achieving the maximum entropy weight value of 22.2%. Pressure field analysis confirms effective elimination of vortex-induced dust agglomeration. The research establishes an optimization model integrating structural parameters of flow distribution device and pressure-exhaust ratio matching， providing an innovative solution for directional dust control in mine environments. Key Words：flow distribution device; long-duct forced and short-duct exhaust ventilation system; pressure-exhaust ratio; numerical simulation; dust control efficiency