印順長老一生治學，範圍極廣，首探三論、唯識，精研阿含、律藏， 對《大智度論》的用力尤其扎實，對於阿毘達磨、大乘論書，對中國的天台、華 嚴、禪、淨，也一樣地都有相當深入的認識。由於印老博綜整體的佛教，從教團 史及思想史的立場，把大小乘各宗的來龍去脈，都看得清清楚楚，所以談任何問 題，都不是從向來佛教學者的一宗一派的觀點出發，而是說出問題的根源及其發 展的過程。 真常唯心系的佛教，雖屬於後期大乘，但它確有阿含佛教的基礎依據，也有 南方大眾部分別說系的基礎，也有經量部譬喻師的影響，印老也特別指出，《起 信論》受有錫蘭佛教《解脫道論》的影響。更有不少的大乘經論如《楞伽經》、《勝 鬘經》、《如來藏經》等作後盾，甚至談到《大乘起信論》的背景資料中，也有古 傳唯識《攝大乘論》的內容。他以講說《起信論》的因緣，把真常唯心論的佛法， 自成一系的條理出來，點明它旳來龍去脈，不用籠統和會，不必擔心發現了諸系 法義的互相出入而會讓人感到懷疑不信。這也正是歷史的方法論，所表現出來的 治學態度及其可信的成果。

　　　　　Master Yinshun has studied Buddhism very widely. He first studied the teachings of Triple 'Saastras and Mind-Only. He has profound understanding of Aagamas and Vinaya pi.taka. In particular, he put much effort in studying Da zhidu lun. He also has deep understanding the Abhidharma Kowa and Mahayana 'Saastras as well as Chinese traditions of Tiantai, Huayan, Chan and pure Land. Master Yinshun has holistic knowledge of Buddhism as a whole. Based on the standpoint of the history of monastic order and the history of Buddhist-thought, he sees clearly the process of development of various schools in Mahaayaana and Theravada Buddhism. Therefore, when he discusses any problem, he does not start from the traditional Buddhologists viewpoint of one school or on sect. On the other hand, he can point out the sources of problem and the process of its development. Though the True-Eternalism and Mind-Only tradition belongs to the Buddhism of later period, yet it really had the foundatism and basis of Aagama Buddhism as well as the influence of sourthern Mahaas^nghika Vibhajya-vaadin and Sautraantika d.r.s.taantika. Master Yinshun also stresses that The 'Saastra on the Awakening of Faith in Mahaayaaya was influenced by Visuddhimagga of Sri Lankan Buddhism. It has also the backup of many Maahaayana sutras and 'Saastras such as La^nkaavataarasuuutra, 'Srimaalaa-si.mha-naada-suutra, Tathaagata-garbha-suutra, and even Mahaayaana Sa.mgraha of old Mind-Only tradition. Taking the opportunity of discoursing the 'Saastra on the Awakening of Faith in Mahaayaana, Master Yinshun listed clearly has the True-Eternalism and Mind-Only School evolved to become and independent tradition. He points out the history of development. He does not use dubious language and traditional viewpoints. He does not worry that the finding of the difference of the teachings among various schools will make people doubt and lose faith. This is also the attitude of academic research and its reliable fruit empressed by history methodology.