|This paper discusses the relationship between mind and principle in Zhu Xi's alternative tenets - either ”mind (xin) is principle (li)” or ”principle is connected with mind” - and also tries to judge whether Zhu Xi's principles are active.In this article, we recognize that Zhu Xi acknowledged ”principle in mind” which can be modified as ”principle originates from the mind”; nevertheless, in his thought concerning investigation, mind is separated from li and belongs to qi, which has both good and evil inclinations.By researching Zhu Xi's works, we find that in his thought about investigation there are three different aspects. First, Zhu Xi found principles from all things, that is, mind and principle are not one. Second, he searched for principles through our inner minds. Ultimately, mind and principle are united in the realm of enlightenment.Finally, although Zhu Xi's philosophy could not fit into the judgments in Mou Zong-San's moral metaphysics of Confucian onto-cosmology, and principles in his thought - such as ”a being and also being active” - do not correspond to Mou's theories either, Zhu Xi's system in fact grasps an active principle of the cognitive mind. Consequently, we still hold that Zhu Xi's cosmological thought displays an active state of ”the oneness of principle and the distinctiveness of the particular” in describing this world.