Abstract: Devadatta has been taken as a demon to murder Shakyamuni Buddha for a long time, and the academic circles have generally approved of this view. In fact, the matter was not so simple. The academic circles at home and abroad have not brought to light the event of Devadatta as yet, because they have only confined to Pali Theravada canons and authority of Vinayapitaka. This paper has a discussion on three respects: records of Mahayana sutras and their relations with Agama sutra and Vinayapitaka, doubtful points of “five hellish sins”, and “five improper ways of gain” advocated by Devadatta. It shows that Devadatta was a most controversial mystical figure in the Indian Buddhist history. He wasn’t a demon, but a great Bodhisattva to be imbued with a sacrifice spirit.