Abstract: The present paper is addressed to the finite element method combined with dynamic photoelastic analysis of propagating cracks,that is,on the basis of [1] by Chien Wei-zang,finite elements which incorporate the propagating crack-tip singularity intrinsic to two-dimensional elasticity are employed.The relation between crack opening length and time step obtained from dynamic photoelaslie analysis is used as a definite condition for solving the dynamic equations and simulating the crack propagations as well As an example,the impact response of dynamie-bending-test specimen is investigated and the dynamic stress-intensity factor obtained from the mentioned finite element analysis and dynamic photoelasticity is in reasonable agreement with each other.