Populism is not a newly-emerged phenomenon. However，it has been gaining momentum across the world in recent years，with significant influences especially in Europe and America. In Europe，the series of crises such as the financial crisis，refugee crisis，terrorist attacks and the Brexit，have led to opportunities for the growing strength of populism. An increasing number of populist parties have claimed seats in national parliaments and even become ruling parties in European state governments. This has not only posed threats to the dominant positions of mainstream parties，but changed，to a large extent，the political discourse and party politics，and even the overall political environment and social order of Europe. Although the populist forces are unlikely to overthrow the European political system due to the practical and legal limits，the ‘spill-over’ effect that populism may result in cannot yet be overlooked. This is particularly true with regard to the values it represents，such as isolationism，protectionism and nationalism，which have extended to the EU level. In recent years，in particular after the 2014 European Parliament elections，the influence of the populist parties have been growing in the EU and brought about a certain degree of risks to the EU’s governance system，the values embodied by the EU and the European integration project itself. The forthcoming EP election in May 2019 will be a significant test to the European mainstream politics as well as the European integration.