Mankind has been grappling with the concept of ”justice” for a long time now. Western and Chinese philosophy both demand a common basis in justice. Modern Catholicism is also concerned with the problem in a social context. This article would like to proceed from the perspective of modern philosophy in discussing justice, using John Rawl's theory of justice as a basis. I would then like to reflect on this concept in the realm of modern Chinese philosophy; then proceed with a discussion of the 1960's Vatican II conference where Pope Paul VI and other dignitaries attempted to expound on Pope Paul II's theory of justice. Finally, I would like to point out that any discussion on ”justice” cannot overlook a reflection on a ”natural law”. It is from this law that we can discuss justice in the realm of religion and theology.