Abstract: Asymmetric vortex flow and associated side force affects the performance of aircraft with slender forebodies flying at high angle of attack, which may happen even when the forebody is axisymmetric and at zero sideslip. This phenomenon can be induced by many factors, the compressibility is one of the posible reasons. This paper primarily focuses on asymmetric vortex flow in high speed. Using pointed tangent ogive slender body, the PIV tests were carried through in high speeds wind tunnel to investigate the asymmetric vortex flow at high angles of attack. The Mach number ranged from 0.4 to 1.2, and angle of attack was fixed to 40°. The results showed that asymmetric multi-vortex flow structure still exist in high speed case, and both Reynolds number and compressibility affect asymmetric vortex flow phenomenon. It was observed that there was a distinct relation between tip perturbation and response of asymmetric vortex flow.