Since the initial stages of 1980s, the global world faced the huge shift. Many security scholars try to challenge and review the mainstream security studies that derived from a combination of Anglo-American, statist, militarized, masculinized, methodologically positivist, and philosophically realist thinking. ¡§The Welsh School¡¨ of Critical Security Studies is one of the most important approach. The Welsh School thinks about security as developing in the light of the Frankfurt School, and brings the tradition of ¡§critical¡¨, ¡§epistemology position¡¨, and ¡§emancipation¡¨ to the security studies. The Welsh School separate the core of critical security studies(CSS) into three concepts: security, emancipation, and community, therefore, this study try to explain and review these concepts. Firstly, CSS tried to ¡§deepen¡¨ the concepts of ¡§security¡¨, deconstruct statism and bring the referent to individual, and then ¡§broaden¡¨ the agenda of security to discuss the traditional and non-traditional issues in the globalization world. Secondly, CSS emphasize the relationship of theory and practice, and expect to achieve their goal-¡§emancipatory politics¡¨. Via the construction of emancipatory community, people could released from contingent and structural oppressions, and create a free and equal environment. Despite the states still the major referent in international institution and security environment, and the main concept of The Welsh School still not practice in contemporary politics, but the first task of CSS is to bring a revision of the world, and then create a comprehensive and humanity security thinking.