On-line nationalism appear to be growing stronger in China`s internet space which have develop rapidly according to economic growth. Also notable is the fact that Korea became one of the main target of on-line Nationalism in China over recent years. The On-line Nationalism in China against Korea grew stronger when the conflict between the two countries was generated by various issues of history and traditional culture problems, territory and security issues, unexpected accidents, etc. Anti-Korea sentiment in China`s online create a downward circle to Anti-China sentiment in Korea`s internet. On-line conflict bring the adverse effects on real bilateral relations between Korea and China. We need diplomatic effort to counteract the on-line nationalism in China. Specially, public diplomacy approach are required to solve the conflict, because this approach means to know partner countries` people, that is to say Chinese citizens before everything else, let them know the truth of issues and exert our influence on them. In particular, it is urgently necessary to establish digital public diplomacy plan for Chinese netizens who advocate on-line nationalism. This article present digital public diplomacy plan toward China`s on-line nationalism as the conclusion.