After the Arab Spring broke out at the end of 20 10, especially since the Islamic terrorist organization "Islamic State" raged in northern Iraq and northeastern Syria, war refugees and economic immigrants from Syria, Iraq, Afghanistan, Libya and other countries entered the EU countries through the Mediterranean Sea and the Balkans, and Greece was the first stop for refugees to enter the EU. These swarms of war refugees and economic migrants have caused a serious social and economic crisis in Europe, leading some political factions and politicians to severely criticize the EU's refugee policy. They believe that the long-term policy of free movement of population and border opening in the EU has seriously affected European national security, led to the infiltration of Islamic terrorism and Islamic law promoters, and further led to the rise of right-wing populism in Italy, Hungary and other EU countries.