「懺法」是佛教中重要的行門之一，惟中國懺法系統化的源起與發展，可追溯至隋朝天台宗智顗（538-597）制作的四部懺法。其後發展至駐錫在五台山大華嚴寺的華嚴宗四祖澄觀（738-839）時，受到影響乃強調懺悔修持的重要性，自身也有修持「方等懺法」。惟考究澄觀所行「方等懺法」的體系內涵為何？何以行懺能達到懺罪作用，甚至達到「解脫」的目的？澄觀是如何進行修懺，其具體步驟為何？又其懺悔思想的核心根源，受到哪些佛學大師的影響？這些都應予以釐清且是值得探討的問題，此乃本研究之主要目的。經筆者深入研究發現：一、澄觀懺悔思想體系乃廣納諸多宗派教理，並集其大成融貫相通；其思想體系已受到「律宗、天台宗、華嚴宗、禪宗」精義教理及儀軌之影響，並於其著作中彰顯出來。二、影響澄觀懺悔思想之源流：（一）天台宗：如何影響澄觀建構一個完整的「懺悔儀軌」，如「十法模式」之儀軌等；其次，在事、理二懺中，要結合禪觀「罪性本空」與「中道實相」之教理。（二）華嚴宗：強調「五悔懺」教理的論述，及華嚴判教的思想。三、澄觀懺悔思想的主要內容：（一）主張要潛修「方等懺法」的教理與實踐。（二）「罪業觀」：有「三罪說」等五種說法。（三）「戒律觀」：有「對『戒律』梵文譯名的正名」等三大類論點。（四）「懺悔原理」：有「《方等》經典或佛菩薩的威神力」等四種原理。（五）「懺悔方法」：有「作法懺」等六種懺悔方法。四、澄觀懺悔法門的簡略儀軌，於本文中略述；其懺悔法門可歸納為：「三懺並重」等四種主要特色。最後，並期待由本文所尋繹出的澄觀懺悔思想與儀軌，能釐清「法會」的真正意涵，效法祖師行懺的精神，進一步提供作懺法研究或實際體驗者的參考。

＂Repentance＂ is one of the major practices in Buddhism. The origin and development of systematized repentance rituals in Chinese Buddhism could be traced back to the four repentance rituals composed by Zhiyi 智顗 (538-597) of Tiantai School in Sui Dynasty. Afterwards, Chengguan 澄觀 (738-839), the Fourth Patriarch in Huayan School, when residing at Da huayan si 大華嚴 寺 in Wutai Mountain, was moved and then emphasized the importance of repentance practice as well as practicing the Fangdeng repentance ritual. Nonetheless, what is the content of the Fangdeng repentance ritual conducted by Chengguan? Why the practice of repentance could lead to repenting of crimes, or eventually being liberated? How Chengguan carried out the practice of repentance and what was the specific procedure? Moreover, which grandmasters have contributed to the core essence of his cognition of repentance practice? The aforementioned inquiries all deserve to be clarified and to be pondered on, which constitute the main purpose of this study. The author discovered the followings after further investigation: 1. The system of Chengguan's repentance thoughts accommodates and integrates a wide variety of schools and doctrines. The influences from doctrines and rituals of schools like Lu (Vinaya), Tiantai, Huayan, and Chan could be found in his teachings and writings. 2. Sources contributing to Chengguan's repentance thoughts: (1) Tiantai: Bringing to Chengguan how to construct a complete repentance ritual, for example, the ritual of ＂Ten-dharma＂ module and so forth. In addition, to integrate the teachings of ＂Empty nature of crimes＂ and ＂Middle way reality＂ in meditative contemplation of repentance rituals of ＂Shi 事＂ and ＂Li 理＂. (2) Huayan: The emphasis on the doctrine of ＂Five repentance＂ and the classification ideas. 3. Major content in Chengguan's repentance thoughts: (1) Doctrine and practice of Fangdeng repentance ritual, and the emphasis of its dedicated practice. (2) Views on karma of crimes: Five statements like Three-nigha teaching and so on. (3) Views on precepts: Three major viewpoints like the correction of translation of terms from Sanskrit related to disciplines. (4) The essences of repentance: Four essences of repentance practices, e.g., powers from Sutra of ＂Fangdeng＂ or from Buddhas or Bodhisattvas. (5) Approaches to repentance: Six approaches to repentance like the repentance by ritual performance, etc. 4. A simplified version of Chengguan's repentance ritual is introduced in this article. Four features are named from such repentance practice, including ＂The equal stress on three types of repentance,＂ and so on. Finally, this research is aiming at the clarification of the real meaning of ＂Dharma assembly 法會＂ via discussion and ponderment of Chengguan's repentance thoughts and rituals, and to follow the spirit of the patriarch's repentance practice, and, furthermore, to serve as reference to future researchers and practitioners.