Europe was still faced with a severe and perhaps even more complicated counter-terrorist situation in 2017 in that a large number of foreign terrorist fighters based originally in Europe were expected to return，a new trend of “pure terror”which was not driven by extremist ideologies had emerged in the home-grown terrorism，and the eye-for-eye terrorist attacks between Jihadists and the extreme-rights were escalating. Accordingly，the European countries had adjusted and strengthened their counter-extremist measures. The year 2017 saw an obviously tightened border control and the reinforcement of hard counter-extremist measures with notable increase in capital and human resources input. These endeavors of policy change，however，haven't touched upon the essence of the enduring policy dilemma which came from the inadequate threat perception. The European countries were still unable to effectively restrain the spreading of the extremist ideologies. Moreover，its policy preferences for putting more emphasis on afterwards “interference”rather than beforehand“prevention”is insufficient to deal with the emerging terrorist problems，and it is even a departure from the preventive nature of an effective counter-terrorism approach. It is not an easy task for Europe to get rid of the dilemma faced by its counter-extremist policies in the near future.