Abstract: By adding a spoiler at the inlet, the problem that the filter paper near the inlet of the upper intake horizontal cartridge dust-collector was easily damaged and invalid, got improved. To determine the best matching scheme of the structural and installation parameters of the spoiler, an orthogonal experiment with three factors and three levels was designed to conduct a CFD numerical simulation. In this experiment, the width of the spoiler b, the installation angle β and the distance from the installation position of the flower plate x, were selected as the factors, and the first order interaction between them was also taken into account. The performance of the spoiler was evaluated by the comprehensive flow distribution coefficient Δ$\overline {{K_\xi }} $, static pressure drop ΔP and ash-hopper particle capture rate η. After variance analysis, single factor analysis and interaction analysis of the experiment result, the parameter matching scheme with better ash-hopper particle capture rate and smaller pressure drop was selected, that was, b=120 mm, β=60° and x=140 mm. With the spoiler, ΔP was still within the appropriate range, Δ$\overline {{K_\xi }} $ decreased by 11.5% and η increased by 19.3%, indicating that the flow uniformity of the filter cartridge and the initial separation effect of particles were improved, which was good for extending the life of filter cartridges.