This article deals with the difference between the philosophies of Cheng brothers, Chen-I and Chen Ho. The difference signifies that the Li-ism, and Hsin-ism, i.e. Chen-Chu school and Lu-Wang school, are derived from those two different philosophies. The author indicates the historical development of those philosophies and the characters of the philosophers. He contends that the difference is critical to the development of history of philosophy in China.