This thesis takes Yamada houkoku’s idea of “sincerity-based”, who is a scholar of Yangming Doctrine of Japan in the late Tokugawa period, as the research object and carried on thorough investigation and analysis of the following major theories that constitute his main ideas: the theory of relationship between meaning and thoughts; the theory of practicing conscience with sincerity; the theory of investigation with sincerity and the theory of benefiting people with sincerity. It not only clarified the main connotation and meaning of the “sincerity-based” idea of Yamada houkoku and expatiated on the relationship between “sincerity-based” idea with the thoughts of Confucius, Mencius, Zhuxi and Wang Yangming in order to reveal the nature and ideological characteristics of Yangming theory in Japan from the case study of Yamada houkoku’s idea.