This paper investigates how conflicts and tension built up between Chinese migrant workers and Korean residents in colonial Korea (1910-1945). This led up to the enforcement of immigration controls by the Japanese authorities and also to a change of the image of Koreans in the Chinese media. The Japanese government adopted a policy to ban Chinese laborers from mainland Japan. This policy implied also, that, by contrast, the Government General of Korea should accommodate Chinese laborers to some extent, as long as the Chinese government accepted Korean people to inhabit and cultivate Manchuria. However, the competition between Chinese and Korean laborers became stronger and the Korean resentment against Chinese wealth in Korea also deepened the emotional gap between the Koreans and the Chinese as time passed. Along with these factors, the Korean nationalistic judgment, that the Chinese authorities oppressed Korean tenant farmers in Manchuria led to the first widespread anti-Chinese riots in Korea in 1927. Furthermore, the Wanbaoshan Incident in 1931 ignited Koreans’ anti-Chinese sentiment, which resulted in bloody ethnic riots and the killing of over 100 Chinese immigrants in Korea. Subsequently Chinese perceptions changed dramatically from Koreans as oppressed victims of Japanese imperialism to their collaborators. The subsequent Mukden Incident cemented this image decisively. However, the anti-Chinese riot not only was ignited by the nationalistic sentiment agitated over Chinese oppression in Manchuria, but also stemmed from long-lasting ethnic discord in colonial Korea. (This article is in English.)