SummaryThe research project is concerned with why the Three Stages Sect was suppressed to be "heresy" and eventually disappeared in Medieval Chinese Buddhism. I point out distinctive characteristics of the Sect that differed from the other Chinese Buddhist sects in three aspects:the structure of the Sangha, the perception of Buddhist eschatology and soteriology,and the hermeneutic strategy of the scriptural citation. The Sect was welcome by commoners, especially female,with its notion of "world-denying love",but its anti-intellectual inclination was resented by scholastic Buddhist sects. After all,the antagonism from the other Buddhist sects is not sufficient to explain the unfortunate destiny of the Sect,because the conflicts among Buddhist sects in the explanation of Buddhist doctrines and precepts occur from time to time. The major factor that leads the suppression of the Sect is that its eschatological view of the present world as the hell offended emperors who regarded themselves to be Wheel-turning kings in the attempt that worked out their territory to be Buddha Land. Through the imperial Bureau of Buddhist Affairs that inspected monks' behavior and writing and preaching,emperors suppressed the Sect. In the Catalogues whose compilation was charged by bureaucrat-monks, the works of the Sect was relegated to be heresy. The suppression of the Sect is an example that the imperial approval is the final standard to decide if a Buddhist sect is "orthodoxy" or "heretical" in Chinese Buddhism. Moreover,though the Sect fell apart after the mid-ninth century,the components of the Sect were circulated in Chinese popular Buddhism. The rise and the fall of the Sect typically represent the autonomous Buddhist development in Chinese population and its tension to the imperial proved Buddhist faith.