Abstract: In order to solve the problems of low dust removal efficiency and excessive particle concentration at the fan discharge port due to the irrational design of the gravity settling chamber, the flow field analysis and structural optimization design of the gravity settling chamber of a certain type of road sweeper was carried out. Firstly, FLUENT was used to simulate the internal flow field characteristics of the settling chamber and the movement of dust particles inside the chamber, and the single-factor effects of the key structural parameters of the settling chamber (angle of the dust shield, width of the dust baffle plate, and the distance of the inlet duct outlet from the top of the chamber) on the settling performance (velocity at the bottom of the chamber, velocity at the front of the outlet, and the along-travel pressure drop) were investigated. Based on Box-Behnken design and regression analysis, a multi-objective response surface optimization of the gravity settling chamber was carried out, and the optimal structural parameters of the gravity settling chamber were obtained. Finally, based on the DPM particle phase model, it was verified that the optimized gravity settling chamber had a better settling effect for dust particles with an equivalent particle size above 0.5 mm.