Abstract: This paper stduy the motion and aerodynamic characteristics affected by boundary layer transition for the hypersonic slender cone re-entry vehicle with the wind-tunnel free-flight testing which the motion freedom is not limited by artificially fixing definite number tripped thread that can produce the change of laminar to turbulent on the 10° halfangle cone surface. The experiment Mach number is Ma=5.0 and we achieve the two Reynolds number's simulation by changing the wind tunnel total pressure P₀. The free flow Reynolds number based on the model length L are 0.84×10⁶ and 1.68×10⁶, respectively. The experimental result shows that artificial tripped thread can not induce the boundary layer transition which have a similar motion and aerodynamic characteristics to the slender cone without tripped thread when the Reynolds number is Re=0.84×10⁶. When the Reynolds number Re=1.68×10⁶,artificial tripped thread can induce boundary layer transition which have a different motion and aerodynamic characteristics to the slender cone without tripped thread and the dynamic stability derivative of the slender cone is below zero which the hypersonic slender cone's motion is steady.