This paper presents a novel technique for coloring stainless steel utilizing a fiber laser. This study develops a processing technology that uses a fiber laser as a laser marking tool, and varies processing parameters such as pre-surface-processing conditions, stainless steel type, line distance, laser power, engraving speed, and laser pulse frequencies to achieve different results. This study investigates the results of the stainless workpiece coloring using optical microscope (OM). This study shows that polished stainless steel 316 exhibits the best engraving effect. With this material, the line distance, laser power, engraving speed, and pulse frequency of the laser change the oxidation thickness. The color of the processed workpiece also changes as the oxidation thickness changes due to the interference caused by the different thicknesses of the oxidation layers. Results prove that fiber laser processing of stainless steel is a promising and efficient technique for coloring stainless steel.