Nowadays, some of the steel parts have been applied induction hardening for better mechanical properties in the automotive and aerospace industry sectors. Induction hardening is commonly used in steels, are high magnetic permeability. Martensite formation was observed application as a result of non-diffusion transformation after induction hardening. At this period, there were chosen three factor such as power supplied, scan rate, distance between work piece and coil, were affected material properties. Developed response variables such as surface hardness and case depth were determined after the experiments were done in the industrial conditions. In this study, data were taken by Taguchi method using L27 experiment orthogonal arrays table. Analysis of Variance (ANOVA) was employed with the help of data taken and regression equation, was determined. As a result of these experiments and analyses, the optimization of the process conditions for induction hardened steel was investigated. As a consequence of the optimization, microstructural characterization using Light microscopy was carried out to determine the effects of the hardness from the outer surface to the center and nevertheless transformations associated with structural changes are investigated and so that results are determined.