Abstract: Based on the variational principle of moving boundaries and considering the contact effect between delamination regions, the nonlinear governing equations are derived for delaminated beams subjected to transverse linear dynamic load, and the corresponding boundaries and matching conditions are given in this paper. At the same time, according to the Griffith criterion, the formulas of energy release rate along the delamination front are obtained. In the numerical calculation, the effects of delamination length and depth, the geometrical parameters and the material properties on delamination growth are discussed. It is shown that the delamination growth of laminated beams is more likely to occur under transverse tensions than under transverse compressions. The possibility of delamination growth increases with the increase of the delamination length and the amplitude of dynamic load, and decreases with the increase of the delamination depth, the ratio of L / h and the E11 / E22 ratio of the material.