This paper ”The study of Chu Hsi's Metaphysics of t'ai-chi (太極,the Great Ultimate), li (理, Principle) and chi (氣, Ether) and the doctrine of ko-wo (格物, Investigation of Things)” is divided into two parts. First, we research Chu Hsi's words about t'ai-chi, li and chi. In this way, we can come to the conclusion that his Metaphysics would point out a vital principle (生生之理). This principle has a perennial living force. According to this article, we could not agree that Chu Hsi's li has not living force. Secondly, the article would discuss Chu Hsi's thought of ko-wu. We mention Chu Hsi's mind and li are distant to each other. In his theory, the subject and object have some distance, too. They are opposite to each other. Thus Chu Hsi's mind and t'ai-chi or man and Heaven could not be entirely united.