Abstract: Asymmetric boundary layer transition of high-speed vehicle induced by the side incoming flow affects significantly its stability and aerodynamic performance. The linear stability theory and \mathrme^N method are used to discover the influence of angles of attack and sideslip on the asymmetric boundary layer transition of HyTRV at Mach 6. Results show that the unstable range of the crossflow instability on the lower surface shrinks and that on the upper surface enlarges gradually with the increasing angle of attack. The dominant frequencies of windward and leeward attachment-line instabilities move respectively into high and low frequencies range. As the angle of sideslip increases, the streamwise vortices on the windward side are suppressed and move into the centerline of the upper surface. The crossflow instability on the windward side span the centerline of the upper surface into the leeward side. Streamwise vortices on the leeward side and lower surface shift into the attachment-line region. The windward and leeward boundary layers become respectively more unstable and stable as the angle of sideslip increases.