This thesis is focused on the matter of defection occurred to the Korean community in North Kando. After the March movement in 1919, it had raised the air of the independent movement outside Korea and simultaneously had reinforced the Korean partisan troops in Kando province. Because of the situation, the Japanese army made an invasion upon the Kando province with ZhangZuolin(張作霖)`s connivance. They had two goals of invasion, one of which was to annihilate the Korean armed troops and then another was to eradicate the resources supporting the forces. The Japanese army, composed of about 20,000 soldiers, gave a battle with the Korean troops in Chungsanli for around a week, but they could not reach their first aim, because the Korean troops could run away from the North Kando with some military achievements. For the second goal the Japanese army cruelly attacked and killed the unarmed Korean, and sat fire to houses in the Korean community. The Koreans faced to the massacre cannot but take defection into consideration. Soldiers had only been in a minority among defectors as compared with civilians. Civilians were regarded as the object to be executed by the reason that they had involved in anti-Japanese action. For their lives and property, therefore, they had no choice but to promise to become a Japanese subject. The Japanese army made principles and details on defection and was so intend on the matter for military and political advantages. Most of defectors over 20,000 had took part in independent organizations, who had been a participant in low rank. Their defection have shown that the basis of the independent movement in Kando was disquieted by the military action of Japan. In the matter of this situation, the Chinese local authorities feared that the defection to Japan might lead to the expansion of Japan in Kando province, and therefore they demanded the Koreans to be naturalized as Chinese. As the Koreans had got an absolute majority in population in North Kando, changing the state of politics in the Korean community was an important problem for all powers, Korean independent organizations, the Chinese authorities, and Japanese army and government.