The main objective is to validate the feasibility and accuracy of a multi-freedom time domain impedance boundary condition for broadband sound propagation problems.The NASA(National Aeronautics and Space Administration) grazing incidence tube experiment data was selected for numerical validation.The linearized Euler equation was solved by a high order computational aeroacoustics approach.The obtained numerical results are in good agreement with both the experimental data and results from single frequency simulation.It is demonstrated that the multi-freedom broadband impedance boundary condition is viable and accurate for the description of broadband sound propagation over impedance surfaces.