“Meng Tzu” had become one of learning devoted to the study classics in Northern Sung. But at the beginning of Sung dynasty, there were tow kinds of power in competition, one is “Respecting Mencius” and the other is “Doubting Mencius”. The former was represented by Wang An-shih; the later was represented by Szuma Kuang. The influence of these tow kinds of power was extended to Southern Sung. The people who was respecting Mencius were Yu Yun-wen and Chu His, and the people who was doubting Mencius was Chao Shou-chih. The objective of this study is to compare the viewpoint of Szuma Kuang “Doubting Mencius” and Yu Yun-wen “Respecting Mencius”, and give explanation.