In recent years, laser surface treatment (LST) has widely used to improve the properties of nickel coatings. LST has many advantages, however, different coating thicknesses require different modes, which can be selected using simulation. In this study, the modeling process is considered and an experiment is conducted to study the effect of LST process parameters on melt pool sizes. The aim of this research was therefore to reveal the dependence of the melt pool depth, namely the thickness of the layer in which the mixing process of components takes place, on the scan speed using a diode laser. With LST by diode laser, the thickness of the processed layer reaches about 500 μm, and the width of the processed surface is about 6 mm.