With the rising Euroscepticism in the UK over recent years，the European question has become one of the most challenging issues in the British diplomacy and domestic politics. There have been fierce disputes over how the EU should be reformed between the UK and EU ever since David Cameron’s Bloomberg speech in early 2013. During 2014-2015 fresh disputes occurred on immigration policy，nomination of new EC President，EU budget contribution etc. The uncompromising stance of the British government in its European policy increased the risks of its isolation within EU and decreased its ability to influence the development of European integration. Both the Coalition and the now Conservative government have proposed that an in/out referendum should be held to determine the UK’s future in the Union following negotiations with the EU to secure some important reforms. At present，the Conservatives，Labour and the Liberal Democrats all support UK’s EU membership within a reformed EU. The rise of UKIP was restrained after the general election，and the number of people against British exit is increasing. The key to future developments of British-EU relations lies in whether British political elites and general public can achieve a balance between national sovereignty，national interests and constructive engagement in the European affairs.