Abstract: A method for identifying unsteady aerodynamic torees of elastic vehicles is presented. A standard measurement equation satisfied by aerodynamic indicial functions is derived from longitudinal small-disturbance equations of elastic vehicles with unsteady aerodynamic forces described by Duhamel's integral.The discrete values of aerodynamic indicial functions in time domain are obtained by using recurrent filter technique. In comparison with other methods, this method has the following advantages: （1） convenience to take the effects of structure deformation into account; （2） capability to identify the unsteady aerodynamic parameters of the w.hole vehicle; （ 3 ） ease to collect initial data; （ 4 ） simplicity of the calculation. Finally, some results of the preliminary calculation for a vehicle are given.