Abstracts In these work, New technique for harden stainless steel 316L and similar alloys which does not harden in response to heat treatments will be developed by laser irradiation .The goal of this study is to investigate the effect of laser wavelengths at the same repetion rate, energy per pulse and number of pluses on different hardening routes for 316L stainless steel by laser surface irradiation. For each hardening route we present the microstructure, modulus and the Hardness of the processed surface and the conditions leading to the best compromise between. highest hardness, reasonable modulus and best homogeneity in microstructure features The results show that the laser treatment improves the properties of AISI 316L stainless steel. This improvement is not associated with distinctive changes in mechanical properties, rather it is attributed to microstructure. In fact the process is complicated and limited to certain laser irradiation conditions depends mainly on the original microstructure.