Abstract: The Lawrence-Gurney model is capable of, through mathematical equations, predicting the final velocity of flyers accelerated by laser beams. This paper, through both theoretical analysis and experiments, studies the applicability of the L-G model. It is shown that L-G model can not describe the driving process well for flyers thinner than 10 μm, due to the fact that the interactions between the laser beam and the flyer are ignored along with a number of simplified conditions to deduce the equations based on the energy and momentum conservation laws. These assumptions and approximate calculation conditions are not satisfied if the flyer thickness is less than 10μm, which would lead to a considerable error in predicting the change of the flyer velocity, the energy coupling efficiency, the momentum coupling coefficient, and the ablated depth of the flyer with the change of the laser energy. Thus, the L-G model should be corrected.