A three-dimensional model of direct heat treatment of a sample surface with a moving laser has been established utilizing the finite element method. Attention is devoted to the preparation of complex boundary conditions of a moving heat source. Boundary conditions of material heat treatment are defined in the form of the heat transfer coefficient with consideration of several effects. Those include general distribution of energy in the laser beam, laser motion velocity, laser axis position outside the sample, and utilization of multiple laser motion tracks over the sample. Various arrangements of sample heat treatment are proposed and computer simulated. Different velocities of laser motion, multiple motion over the same track, and simple motion over a number of tracks are investigated. The temperature distribution in the sample and the depths of material heat treatment are evaluated. The simulation model can be used for temperature prediction during laser surface treatment of materials.