In hypersonic winds, special tests for dynamic stability parameters usually use a model tail to support forced vibration. Supporting disturbances under dynamic conditions may result in unsteady flow structures such as shock-induced separation, vortex motion and rupture. The nonlinear aerodynamic loads generated by such structures lead to difficult and complex techniques for supporting interference under dynamic conditions. In the paper, the numerical simulation of the tail support interference of the special wind tunnel test with dynamic three-dimensional unsteady N-S equation is carried out. Numerical simulation and experimental comparison of three different supports were carried out for the 7° blunt cone model. For the static aerodynamic coefficient, the greatest influence of the support disturbance is the drag coefficient. The pitch damping derivative under dynamic conditions is very different, and the support interference is up to 40%. Support interference under dynamic conditions is much more complicated than static conditions. The control law of support interference under static conditions cannot be directly applied to dynamic unsteady conditions. It is considered that the tail support of this form design has less dynamic flow field interference to the aspirating hypersonic vehicle and meets the needs of the dynamic wind tunnel test.