An excellent parole system is able to prolong the effectiveness of correction. It can also evaluate the important reference criterion of the superiority and inferiority of criminal justice policy. Futhermore, the parole conditions of R.O.C has always been reformed recently, it reveals the importance of parole system. Thus, the discussion of parole system can work on the objective analyses and valuable disputations. In the other hand, if we can extensively refer to the experience of various nations as a model, it will help to extend our (i.g R.O.C) parole system. In view, this article first discusses the characteristic of parole, and then introduces various nations' parole system and compares the differences. This article will enable us to know the trends and differences of parole system in various nations, and then expecting to provide a reference to the rsearchers.