Laser materials processing has been used in the industry for drilling, cutting, welding, scribing, and etc. In most of the scientific papers, the authors assume that the laser energy imparted to the material is transformed into heat. This induces phase transformation as melting, fusion, sublimation, or vaporization. It is known that the atoms and ions are produced in high density plasma plume due to laser irradiation. In order to clarify microscopically the ablation and vaporization phenomena the material must be regarded as an aggregate of atoms or molecules, not as a continuum. It is difficult to observe the processing phenomena experimentally, because it occurs in very small region and for a very short time interval. Consequently, the phenomena must be elucidated by theoretical analyses or simulation to some extent. Laser ablation of nickel has been investigated by molecular dynamics simulation. The process of determination of equilibrium in the atomic system was examined as a first stage of simulation. The influence of the laser energy fluence on the process of ablation was studied. The threshold for ablation, values of the velocities of the ablated atoms were obtained.