Abstract：Sonoprobe method has been applied in non-destructive inspect of bolt-supported project，with the fundament that dynamic transient excitation causes the elastic vibration of bolt，and flaws can be estimated or dedermined by analysing transient response of bolt. In the mechanics field this method means that if the information of disturbance resource，boundary conditions and initial conditions has been given，the dominant equation describing medium motion could be established and then the dynamic response solved. Usually it comes down to the question of initial value or initial-boundary value of hyperbolic equation or hyperbolic- diffusibility equation. FE solution is made on the hyperbolic equation，based on acoustic parameters，such as velocity of sound，vibration range，wave shape，etc，when inspecting interior flaws of grout of bolt. The obtained estimation is more credible with the spectrum aberration taken into account.
