摘要： 本文主要探讨的是我国减刑制度的正当性依据，认为“为什么可以减刑”的理由，是刑罚执行的特殊预防目的使然。1．根据再犯可能性考察，已经消除了人身危险性的犯罪人没必要执行全部原判刑罚；2．从刑罚效益的角度考虑，多余的刑罚是一种浪费；3．从心理学的角度来看，减刑使犯罪人已有的善行得到鼓励和保持。同时还认为，关于“为什么减刑要有一定限度”，是刑罚执行的一般预防目的使然。刑罚的一般预防目的要求刑罚必须被严格执行；刑罚的一般预防目的要求减刑不能无限度；刑罚的一般预防目的要求减刑不能有损审判的严肃性。最后，文章对我国现行减刑制度的正当性进行了认真反思。

关键词: 减刑制 , 正当性 , 一般预防 , 特殊预防

Abstract: This article makes a discussion about the justifiability grounds for the commutation system of China，and proposes that the reason why the punishment can be commuted lies in the purpose of special prevention for punishment ution．Firstly，there is no need to ute all the punishment because of the little possibility of committing crime again．Secondly，considering the efficiency of punishment，too much punishment is a waste．Thirdly，psychologically，commutation encourages and keeps prisoners’good conduct．Meanwhile，it’s necessary to give commutation some limitation to satisfy the general prevention of punishment ution．The purpose of general prevention for the punishment ution requires that the punishment be ute rigidly，and the punishment can’t be commutated without limitation，and the commutation can’t influence the solemnity of the trial．In the end，the author made a discussion about the justifiability of the current commutation system．

Key words: commutation system, the justifiability, special prevention, general prevention