The relationship between Britain and European integration has always been regarded as a significant perspective to observe the process of European integration and the British political ecology. Indeed, since the UK participated in European integration, Britain has always been described as an aloof, awkward and passive partner. Meanwhile, after 40 years of successful development, European integration is being placed at a new crossroads. Also, the power and global influence of the UK is changing and adjusting. On 8 May 2015, the Conservative government won the general election with majority votes, and a referendum on British membership of the EU would be held in 2017. Once again, “in or out” question has given rise to heated discussions on the future of UK-EU relationship, which is worthy of us in-depth analysis. Therefore, this paper introduces politics, economy and security within the UK-EU relationship in different periods through historical analysis, and in order to explain why the UK has always kept passive and changeable attitude in European integration. Undoubtedly, all of these factors have exerted impacts on the relationship between the UK and the EU. From my pointe of view, based on current close economic ties with 4 | P a g e the EU and world situation, I think Britain would not leave the European Union. However, the UK would still act as an awkward partner during the interstate negotiations, and put its national preferences as priority in the future of European integration.