Why has not Britain joined euro until now? This is an attractive issue. The purpose of this paper is to realize the real reasons. Hence, this paper analyzes the euro policies of Thatcher Government, Major Government and Blair Government. Before interpreting British euro policies, this paper explains the process of British EU membership. In addition, this paper introduces the story of EMU which is relative to euro. Most importantly, here this paper takes ¡§Europeanization¡¨ framework as a study tool to examine British euro policies. Through ¡§Europeanization¡¨ framework, this paper proposes many factors affecting British euro policies, including ¡§goodness of fit,¡¨ ¡¨veto players,¡¨ ¡§timing,¡¨ ¡¨political beliefs and organizational cultures,¡¨ ¡§the costs of institution changing¡¨ and so on. Thus, this paper concludes that Britain hasn¡¦t joined euro until now owing to many factors.