The technique of the thermal boundary layer research near a metal surface on heating in air is considered by a method of laser refractography. The technique of a light beam trajectory modeling in a thermal boundary layer of the heated up surface is described, the beam displacement calculation in heterogeneity and a corner of an output beam from the heterogeneity are resulted, the boundary layer size and the heated temperature value is defined. The laser beam experimental images are submitted by spreading through a boundary layer of the heated up surface. The comparison of calculated and experimental results is carried out.