A numerical study of the expansion of a laser-induced plasma is given by using of techniques of computational fluid dynamics. According to the experiment results reported, the density of electrons is assembled on the surface of the ionization area. In the present simulation, the model is considered as an expansion of plasma bubble in air. The laser energy is absorbed by the surface of the plasma bubble facing to the laser beam. Numerical results show the elongation of the bubble along the laser beam direction, which agrees with the experiments.