Based on a set of experiment picture collection, a 3-point bending specimen model under dynamic load is analyzed in two ways: one is derived by using vibration analysis method with consideration of equivalent system stiffness and damping. The other is using finite element method for ABAQUS software. With the picture taken by a high velocity camera, a measure method for CMOD (Crack Mouse Opening Displacement) is introduced. Dynamic stress intensity factor K1 is compared in two methods and CMOD comparison is carried out between experiment picture collection and ABAQUS result. Example is given in the last part to demonstrate the application of the result in this thesis to the impactor analysis.