The aim of this study is to clarified how the company can achieve a sustainable competitive advantage (SCA) based on the knowledge management (KM); KM has been gaining attention in last decades as one of the most important strategic process to achieve SCA for the companies, it's not easy for any company to achieve a competitive advantage and the situation become more difficult to sustain this competitive advantage in world characterized by the rapidity of the changes; this changes that based predominately on the innovation; the most innovation that make the company archive SCA is the innovation based on the tacit knowledge; for that we will explain in this paper the relation between the innovation and the KM as a strategic process to achieve the SCA for any firm.