The social identity is a complex and resourcefull research domain which have benefited from a large number of conceptual, methodological and experimental studies. The goal of this publication is to present some of the significant scientific contributions concerning the development of the social identity, as a part of the self concept of person. Are discused and analyzed the significances of the social identity concept related to self identity concept and presented the main perspectives of approach and the explanatory psychosocial theories regards the mechanisms of construction of the social identity.