何謂天主教社會理論？最有資格、權力及責任回答此一問題者，自然是教會當局。因此教宗的通諭以及大公會議的文獻成為本論文的出發點。本論文將從教會的宣示中，綜合天主教社會理論的核心議題，並論述各議題的相關性及其推論的一致性。本文將特別關照到一項普遍價值原則，在社會生活的具體顯示。所以我們的論述方式依推論過程逐次顯示議題以說明，何謂天主教社會理論，甚至為何天主教理論。為了達到以上目的，本文除了說明論文目的及型式的前言之外，計分一、基督化人學。二、社會運作原則。三、信仰、理性與實踐。四、在歷史中的天主教社會理論。五、結論各節。

What is the social theory of Catholic Church? The Church herself is obviously the most qualified and responsible institution to answer this question. Hence, papal encyclicals and the documents of Ecumenical Councils will be the key sources for this paper.Inspired by the Church’s official teachings, this paper will attempt to integrate the core value of Catholic social theory issues, and discussed its relevance and consistency. This paper will pay special attention to the value of universal principles and their application to all walks of life.This paper intends to explore what Catholic social theory is and why and is divided into several parts: the preamble that includes the purpose and the type of paper; first section, Christological anthropology; second section, Social practice principles; third section, Faith, reason and practice; fourth section, Catholic social theory in history; fifth section, Conclusion.