From the perspective of the "Eastward Spread of Western learning", KANG You-wei's Deep Meaning of Mencius had distinct characteristics of the times in the late Qing Dynasty. In The Deep Meaning of Mencius, KANG integrated Chinese tradition with Western evolutionism. He discovered in Mencius the applicability of evolutionism in China, and put forward his evolutionism of "three eras", emphasizing "time", "benevolence" and periodical development. KANG also tried to rectify evolutionism translated and advocated by YAN Fu. Representing the dual variation between tradition and times, and reflecting the wisdom and courage of integrating Chinese and Western thoughts, KANG's evolutionism in The Deep Meaning of Mencius is significant for us to deal with Chinese and Western cultures.