Abstract: In this study,an FBS -No6.3 two -stage axial -flow local fan was selected as the research subject. Numerical simulations were conducted to investigate the effect of inlet guide vanes (IGVs) on fan performance. A combined approach of single-factor experiments and orthogonal experimental design was employed to investigate the effects of three primary structural parameters—the axial spacing between the IGVs and the first-stage rotor blades,the number of IGVs,and the IGV stagger angle—on the internal flow field and aerodynamic performance of the two-stage axial-flow local fan,and the optimal combination of these parameters was identified. The results indicate that the axial-flow fan equipped with IGVs exhibits superior aerodynamic performance compared with the prototype fan. Specifically,both the number of IGVs and the stagger angle significantly affect fan performance,whereas the axial spacing between the IGVs and the first-stage rotor blades has a relatively minor influence. The single-factor experiment results indicate that optimal matching with the first-stage rotor is achieved when the number of IGVs is nine. The installation of IGVs significantly improves both the total pressure and efficiency of the fan. At the design flow rate,the optimal configuration with nine IGVs,a stagger angle of -5°,and an axial spacing of 35 mm results in a 198 Pa increase in total pressure and a 0. 27 percentage point improvement in efficiency compared with the prototype fan.