Boronized layer was prepared on carbon steel substrate by pulse electrodeposition in KCl-NaCl-NaF-Na2B4O7 molten salts. The orthogonal experimental design was used to study the influence of pulse electrodeposition parameters on the thickness of boronized layer. The distribution of boron content of the boronized layer was measured using the glow discharge spectrometry (GDS) and the depth from the surface to the inflection point was taken as the layer thickness. It was found that the order of significant factors for the thickness is electrodeposition temperature > electrodeposition time > current density > borax content > duty cycle. Based on the results of the range analysis, the maximum thickness was found at a current density of 120mA/cm2, a electrodeposition temperature of 900°C, a electrodeposition time of 120 min, a duty cycle of 10%, and a borax content of 0.04 mole ratio.