Abstract: In order to reveal the effect of wall temperature on the instability mechanism of high-speed streamwise vortices, the global stability analysis method (BiGlobal) was used to study the streamwise vortex instability characteristics of high-speed transition research vehicle (HyTRV) at different wall temperatures. The laminar basic flow was obtained through direct numerical simulation. The Mach number of incoming flow was 6, the unit Reynolds number was 1.0 × 10⁷/m, the static temperature was 79 K and the angle of attack was 0°. Three wall temperature conditions were set, T_w=150, 300, 450 K, and the ratio of wall temperature to recovery temperature ranged from 0.25 to 0.76. The results show that the curling degree and the thickness of the streamwise vortices increase with the increase of wall temperature. Wall temperature does not change the types of unstable modes in the streamwise vortex region, but affects the growth rate of main unstable modes and the types of dominant modes. With the increase of wall temperature, the growth rate of unstable modes increases. When the wall temperature is in the range of T_w=300~450 K, the dominant mode is the unstable mode O3, whose shape function mainly lies at the shoulder of the streamwise vortices. When the wall temperature is T_w=150 K, the modified Mack mode increases greatly upstream, and can be transformed into shear layer instability mode downstream, which may trigger the streamwise vortex transition. The results of e^N method based on global stability analysis show that the streamwise vortex transition is advanced by 127 mm when the wall temperature rises from 150 to 300 K. When the temperature rises from 300 to 450 K, the transition is further advanced by 110 mm.