Starting from 6th Century B.C., a tide of Sramanic movements raised against the Brahmin religions in the Northeast part of India, signifying that Indian religion and civilization had stepped into a new stage. Among these movements, Jainism and Buddhism are two of the most famous and still circulate in the world today. In the Chinese translation of early Buddhist Canon such as The Four Agamas, details of debates between Buddha and Jainas on karmic theories are recorded. These materials on Jainism in Chinese language are precious and they demonstrated the differences between the two religions in their doctrines and practices. This paper will demonstrate the Buddhist critique on the karmic theory in Jainism by exploring the Chinese Buddhist translations. This comparison may deepen our understanding on both the two religions and the competition between different Sramanic movements at that time, and shed lights on different ancient Indian thoughts besides Buddhism.