With the continuous upgrading of hypersonic vehicles, a new design requirement for imaging window is put forward, that is, conformal window to improve aerodynamic characteristics, which requires the supersonic cooling film and optical window to maintain the same curvature shape as the aircraft body.This paper investigates the mixed-layer flow evolution on a convex wall (CV). The flow field structure of the mixed layer is captured using a nanoparticle-based planar laser scattering technique in a <i>Ma</i>=6 hypersonic static wind tunnel, combined with fractal dimension to investigate the location of mixed-layer instability. Results of pressure, and impulse of compression (<i>Ip</i>) evolution along the flow direction were obtained using numerical simulation techniques. The results show that the total incoming pressure (<i>P<sub>0</sub></i>) has a significant effect on the flow evolution of the mixed layer, and as <i>P<sub>0</sub></i> increases, the ratio of static pressure (RSP) decreases, the position of the mixed layer instability is delayed, and the flow velocity of the typical vortex structure increases. The presence of favorable gradients at the CV wall allows the pressure to drop along the flow direction, and the pressure is boosted when the supersonic air film along the tangential direction of the wall is in operating condition. However, as <i>P<sub>0</sub></i> increases, RSP decreases with it, and the lifting effect of the pressure on the CV decreases. The flow field is affected by the expansion effect of the CV, and <i>Ip</i> decreases along the flow direction. The supersonic air film can weaken the expansion effect on the CV and thus suppress the decrease of <i>Ip</i>. The change rate of <i>Ip</i> (<i>ΔIp</i>) is significantly affected by <i>P<sub>0</sub></i>, in the range of bending impulse |<i>I<sub>Φ</sub></i>|=0.191~3.62, <i>ΔIp</i> decreases from 178.67% to 12.02% when <i>P<sub>0</sub></i>=0.5Mpa and <i>ΔIp</i> decreases from 40.38% to 5.64% when <i>P<sub>0</sub></i>=1.0MPa. <i>ΔIp</i> decreases as |<i>I<sub>Φ</sub></i>| increases, but the decrease weakens as <i>P<sub>0</sub></i> increases. The results reveal the flow evolution law of hypersonic mixed layer under the influence of convex curvature, and provide a certain reference for the shape design of hypersonic vehicle to achieve aerodynamic drag reduction and thermal protection characteristics.