This study examines the Younghae’s the movement vindicating the innocence of the founder of Donghakfrom the perspective of Kang Su, a key figure in the Donghak denomination. The significance of the Younghae’s the movement vindicating the innocence of the founder of Donghak can be summarized in the following points. First, this movement was the first to socialize the ideas of Donghak. Second, the movement was carried out by the Donghak denomination and the forces of change. Third, based on the organization of the Donghak denomination, it has moved beyond regional limits. Fourth, this movement became the origin of the movement vindicating the innocence of the founder of Donghak that developed nationwide in 1892~3 and the Donghak Peasant Revolution of 1894. Because of these points, the territorial the movement vindicating the innocence of the founder of Donghak is receiving new light. This study seeks to examine the perspective of Kang Su, a key figure in the Youngyae’s the movement vindicating the innocence of the founder of Donghak and the Donghak denomination. The Younghae’s the movement vindicating the innocence of the founder of Donghak is of great significance in that it was the first to socialize Donghak’s ideas. It is also significant that this movement was carried out by the Donghak denomination and the transformative forces together, so it went beyond regional limits and put forward an ideological orientation based on Donghak. Kang Su was a native of Yeongdeok, Gyeongsang Province, and after the purity of its founder, Choi Je-woo, he assisted Choi Si-hyung in expanding the religion. Choi Si-hyung and Kang Su initially objected when Lee Pil-je entered the Younghae and demanded the movement vindicating the innocence of the founder of Donghak. However, since Lee Pil-je had rallied the dynamics and transformation forces of Younghae and Yeongdeok, he was in favor of the last. Kang Su, along with Lee Pil-je, played a leading role in a series of processes such as mobilization of participating personnel, occupation of the Younghae, dispersal and flight. After the occupation of the Younghae, Kang Su strongly opposed Lee Pil-je’s attempt to advance into Yeongdeok. At this point, the position of precipitation was clearly visible. The reason for this was, first, that the original purpose of the Younghae’s the movement vindicating the innocence of the founder of Donghak had been altered. Second, it was because of the heavy casualties in the process of occupying the territorial sea department. Thirdly, on a personal level, his brother Kang Mun died during the occupation and had to be funeral. For these reasons, Kang Su opposed his entry into Yeongdeok, his residence. Kang Su joined the movement vindicating the innocence of the founder of Donghak under the direction of Choi Si-hyung, but opposed it when Lee Pil-je changed the direction of the movement to the transformation movement. In particular, when Lee Pil-je murdered the governor of Yeonghae and tried to advance into Yeongdeok, he decided that Lee Pil-je’s actions were outside his original purpose as a dogmatic believer, so he opposed it and stopped the transformation movement. In this respect, it can be confirmed that the precipitation was intended for dogmatic purposes, unlike the Lee Pil-je. In other words, he had the characteristics of a religious man rather than a transformative activist, and this aspect of him is consistent in later denominational activities.