  In this paper, Bohmian mechanics is introduced to the intense laser-atom
physics. The motion of atomic electron in intense laser field is obtained from
the Bohm-Newton equation. We find the quantum potential that dominates the
quantum effect of a physical system becomes negligible as the electron is
driven far away from the parent ion by the intense laser field, i.e. the
behavior of the electron smoothly trends to be classical soon after the
electron was ionized. Our numerical calculations present a direct positive
evidence for the semiclassical trajectory methods in the intense laser-atom
physics where the motion of the ionized electron is treated by the classical
mechanics, while quantum mechanics is needed before the ionization.
