Upon the end of the Cold War，a wave of neonationalism swept the whole world，to which China and South Korea were no exception.With a common history of invasion and humiliation by Western colonialism，nationalism assumed similar features in China and South Korea，in that they both were an “impact-selfdefence” type of nationalism.There was a tradition of China and South Korea joining hands to combat invasions by Western powers.Nevertheless，in our contemporary era，the emergence of neonationalism under novel historical circumstances has had a negative impact on the bilateral relations.This article analyses and discusses the reasons，features，and impacts on bilateral relations by this type of neonationalism in both countries，on the basis of which it offers some reflections on how to advocate an appropriate kind of patriotism and to overcome narrow-minded，radical nationalism.