On January 31，2020，the UK withdrew from the EU formally，which ended its 47-year EU membership and launched the “post-Brexit era”. However，the UK experienced a series of severe challenges in the year. Firstly，in spite of the agreement it sealed with the EU at the end of 2020，a number of issues have been left unsolved，which are critical to the relationship between the two sides. Secondly，the spread of the novel coronavirus led to a declining trust and support rate towards the Conservatives，which has exposed the divergences within the Tories on political ideology. And at the same time，the sharp economic recession under the dual impacts of Brexit and pandemic that the UK was trapped in，to a large extent，constrained the governance capacity of the UK government. At last，the nationalist sentiment in both Scotland and Northern Ireland have risen as a result of the Brexit and the pandemic，posing a certain threat to the stability of the UK.