The purpose of this study is to explore and analyze the life and thought of Yin-shun, the most important Buddhist monk since the Sung Dynasty. His life reflects not only his spiritual progress but also the deterioration, decline, and change in quality of Chinese Buddhism. His thought, expressed through his more than forty five published books, is to promote the revolution of Buddhist thought through his systematic research and profound understanding of the Buddhist sutras and sastras. The study of Yin-shun's life is classified into the pre- Buddhist contact period, the grouping period, in search of the Dharma, the formation and maturity of thought, the spread of the Dharma, and the reclusive life. His methodology (to study the Buddha Dharma by means of the Buddha Dharma) combines scholarly research and religious practice to pursue and realize the truth. The study of Yin-shun's thought is limited to his views on religion, the Agama Sutras, doctrinal classification, Ch'an, Pure Land, and jen-chien fo-chiao (Buddhism in the human world). His view on religion covers his basic belief of Buddhism which serves as the basic principle to understanding his writing. His view on the Agama Sutras corrects the misunderstanding by the traditional Chinese Buddhists who have looked down upon them as the teaching of Hinayana. Chinese Buddhism since the Sung Dynasty has reduced to either the Ch'an School or the Pure Land School. Therefore, his views on Ch'an and Pure Land are thoroughly examined. His doctrinal classification brings the historical development of Indian Buddhism into consideration and sets him apart from those of T'ien- t'ai, Hua-yen and T'ai-hsu. His prescription for modern Chinese Buddhism is jen-chien fo-chiao which manifests his compassion through his realization of Prajna. Finally, Yin-shun's contribution to Chinese Buddhism are examined through his interpretation of jen-chien fo- chiao, Nagarjuna's emptiness, Chinese Buddhism, relationships between Buddhism and Confucianism, and his other scholarly accomplishment.