Abstract: The boundary layer developed along the side wall of the test section is one of the main factors affecting the accuracy of the aircraft semi-span model test data. The numerical simulation method was used to verify the effect of vortex generator on reducing the boundary layer influence. The influence of design parameters such as installation angle, structure size, installation position and number on the velocity distribution inside boundary layer was analyzed in detail. The strength of wake vortices and development along the flow direction were discussed. The results show that the wake vortices generated by the vortex generators are capable of improving the velocity distribution inside boundary layer, therefore decreasing the boundary layer thickness and reducing the influence of the boundary layer. The trailing edge of the vortex generator should be slightly higher than the thickness of local boundary layer. The installation angle, position, number must be reasonably designed to reduce the influence of the vortex generators on the main flow of the test section. Based on the results, vortex generators that can be used in the half-model test section of 2.4 m transonic wind tunnel is preliminarily designed, which are capable of reducing boundary layer thickness for about 66 percent in model area, and the influence on centerline Mach number is less than 0.003. Research results can be used for further vortex generators applications in wind tunnel tests.