Since July 2017，the Brexit process has been experiencing ups and downs. Theresa May’s administration has been softening its position of a “Hard Brexit”，seeking to compromise with the EU on Chequers plan. However，the final Brexit deal is still up in the air and the possibilities of a no-deal Brexit and a second EU referendum still exist. The complexity and uncertainty of Brexit have profoundly affected the development of the politics，economy and social reality in Britain：first of all，the divergence on Brexit weakens the original political and economic consensuses in the UK and forms new divisions on European issues. There are challenges and crises especially for British party politics，democratic governance and national unity. Moreover，though Britain is still a member of the EU，the uncertainty for a long time in the path to Brexit has gradually brought pressure on British economy. It retards the UK economic growth，negatively affects investment and employment and binds fiscal and monetary policies. Thirdly，the UK’s international role and foreign policy are under the pressure to be adjusted. All in all，no matter whether these challenges and pressures are regarded as a short-term phenomenon in the Brexit process or as an inception of a long-term national transformation，they are closely related with the final outcome of Brexit and profoundly affects the future of Britain.