天台宗的思想體系由智者大師智顗(538-597)所建立。筆者前曾為文嘗試將其理論匯整統合，以建構全體完整的天台教觀體系。本文則在進一步的論述其細部之內容與相互對應關係，尤其是觀門部分三種止觀之「漸次止觀」的內涵，及其與教門化法四教，特別是圓教與別教的關係，為一天台學的重要論題。此外，本文亦對化法四教本身的各教間之區分與關連作一詳細分析說明。

本文之研究成果有：
一、天台教門之化儀四教、五時說，應捨棄約教部的說法，僅保留約教相說。應捨棄的理由，不是智顗沒有主張時序義的五時說，而是其已為現代學界證實為不符史實，並且亦非天台思想所必須。捨棄之不僅不影響天台之思想體系，反而讓天台教義之妥適性與一致性更佳。化儀四教說亦非全盤錯誤。其在約教相論的意義之下實可成立，並具有如四悉檀因機設教的重要意涵與價值。

二、本文將天台思想體系之四大要目：教門「化儀四教」與「化法四教」、觀門「化儀四觀」與「化法四觀」之六種對應關係均一一推得，最後並將全部關係作一綜整。經由此各要項之一一對應，可發現天台思想教觀體系之完全融通與相契一致。相信亦有助於對天台思想系統之更詳盡的了解與融會貫通。

三、本文亦對觀門之化儀四觀（圓頓、漸次、不定三種止觀及祕密止觀）所含的具體行法之內容作說明。並再度補充證明，漸次止觀是屬於觀門化儀，乃是由藏教觀、通教觀、別教觀，漸次修習到圓教觀，並不能僅等同於圓教觀（一心三觀）。所以，並非如湛然（711-782）、智旭（1599-1655）與有些現代學者所主張的，漸次止觀攝屬於圓教（或圓教觀），而是漸次止觀包含圓教觀。

四、本文「附論」重申天台宗非以圓教含容一切教法而單只主張圓教。明確界定圓教之教化對象僅限上根人或根機成熟眾生。並詳論藏、通、別、圓化法四教本身之各教（含觀法）的區分與關連，尤其是圓教與藏、通、別教之關係及四教間的接會。

The ideological system of T’ien-t’ai Buddhism was established by Master Chih-I (智顗538-597). I had built a wholly integrated ideological system of T’ien-t’ai Buddhism by unifying Chih-I’s theories in my earlier papers. The aim of this paper is to research the contents and their corresponding relations between fundamental elements of the ideological system. This paper also explains the elements of “Gradual Way of Samadhi and Contemplation”（漸次止觀） and it’s relationship with Perfect-teaching （ 圓教） and Separate-teaching（別教）. The latter one is an important thesis in T’ien-t’ai Buddhism study.

The achievements of this paper are as follows：
a. The meaning of “Four Teachings of Teaching Way”（化儀四教）and “Five Periods of Teaching Time”（五時） from the point of view of “Separation of Scriptures”（教部） should be taken away, but the meaning of them from the point of view of “Characteristics of Teaching”（教相） should be kept. The reason of why should take away the meaning is not because Chih-I didn’t maintain the viewpoint of time meaning of “Five Periods of Teaching Time”, but because it has already verified for not according with the historical facts and it is not necessary for theory of T’ien-t’ai Buddhism. Taking away the meaning will not influence the integrity of the ideological system; on the contrary, it will make the ideological system more proper and consistent. Furthermore, “Four Teachings of Teaching Way” are not totally wrong. They stand with the meaning of “characteristics of
teaching” and they possess important meaning and value as “Four Siddhanta”（四悉檀）.

b. There are four major elements of the ideological system of T’ien-t’ai Buddhism. They are “Four Teachings of Teaching Way”（化儀四教）and “Four Teachings of Teaching Contents”（化法四教） in aspect of teaching , “Four Ways of Practice of Contemplation”（化儀四觀） and “Four kinds of Contemplation”（化法四觀） in aspect of practice. This paper deduces the six corresponding relationship between these four major elements and combines them into one. By this way, we can find out that the ideological system of T’ien-t’ai Buddhism is wholly consistent and it will help us more exhaustively understanding of the system.

c. This paper also explains the concrete contents of practice of “Four Ways of Practice of Contemplation” which involve “Perfect and Immediate Way of Samadhi and Contemplation ”（圓頓止觀）,“Gradual Way of Samadhi and Contemplation” （ 漸次止觀） , “Indefinite Way of Samadhi and Contemplation”（不定止觀） and “Secret Way of Samadhi and Contemplation”（祕密止觀）. Besides, they are proved again that “Gradual Way of Samadhi and
Contemplation” belongs to “Ways of Practice of Contemplation”（觀門化儀）, and it means gradual practice from “Contemplation of Tripitaka Teaching”（藏教觀）, “Contemplation of Universal-teaching” （通教觀）, “Contemplation of Separate-teaching”（別教觀）to “Contemplation of Perfect-teaching”（圓教觀）, instead of merely being equal to “Contemplation of Perfect-teaching”（i.e. “Threefold Contemplation in one single Mind” 一心三觀）. So the opinion advocated by Zhan-ran（湛然711-782）, Zhi-xu（智旭 1599-1655） and some modern scholars that “Gradual Way of Samadhi and Contemplation” belongs to “Perfect-teaching” （ 圓教） or
“Contemplation of Perfect-teaching” is not right. It is really true that
“Gradual Way of Samadhi and Contemplation” includes “Contemplation of Perfect-teaching”.

d. In addition, this paper declares that T’ien-t’ai Buddhism preaches not only “Perfect-teaching”, but also all other teachings. Those who are taught by “Perfect-teaching” are only good or matured “roots of practice”（根機）. This paper also discusses the distinctions and relations between each teachings of “Four Teachings of Teaching Contents”.