On the basis of Gurney equation and the equation of state considering phase transition for metals, a model to calculate the movement of the laser driven flyer is proposed in this paper.This model can be used to determine parameters related with critical initiation of explosive, such as deposited laser energy, thickness of ablation layer and flyer, flying distance and so on. The calculated results are consistent with the experiments. Further considerations of ionization, ablation and two dimensional effects are possible to be included in the model.