PE is manufactured by Transysteme with the method of thermocompression of PE powder. This company irradiates PE by YAG LASER. We compared the physical behavior of both samples. The DSC reveals a high and similar crystallinity of PE, before and after YAG LASER treatment. Weattability between PE and Li-PE are similar at about 37 mJ/cm². The difference appears with respect to the surface profile and composition: the roughness is 0.20 µm for PE and 0.29µm for Li- PE. XPS reveals many traces of stripping agents on PE. YAG Laser produces a surface cleaning effect. Biological tests reveal a non-toxicity of the polyethylene powder, an improved proliferation and vitality of L132 cells on Li-PE with respect to untreated PE. We have a 4-fold improvement of proliferation and a 2-fold improvement of vitality on Li-PE with respect to PE. As to morphology and cell adhesion behavior, we have no differences between both samples. Thus the irradiation process of PE by YAG LASER improved the biological behaviors of this polymer due to changes in roughness and to surface cleaning.