Abstract: The aero-optical distortion was caused by the flow field around an optical dome with supersonic (Ma_c=3.0) gas injection in a hypersonic (Ma_∞=6.0) gun wind tunnel. A wavefront measurement method based on background oriented schlieren (BOS) was adopted to obtain the distorted optical wavefront. There is a positive correlation between bore sight error (BSE) and the pressure ratio of jet (PRJ). Under jet condition, BSE is relatively small when PRJ=1, and PRJ has no significant effect on the higher-order aero-optical distortion. The effect of micro vortex generator (MVG) on BSE is not obvious, although the effect of MVG on the high-order aero-optical distortion is obvious. Based on the correlation result of wavefront, after the application of MVG, the structure size of wavefront is reduced from 0.2A_D to 0.1A_D. The decrease of structure size effectively inhibits the high-order aero-optical distortion and improves the stability of wavefront.