The Iranian legislative system after Islamic revolution in the way of administrating Islamic orders, replaced the customary punishments by Islamic punishments. Expect in the section of discretionary punishments that the judge can choose the type and quantity of punishments; in the other sections such as definite punishment, its type and quantity were determined so that wrong doing of it is illegitimate. In other word, because of special expedients that holy legislator has considered, the possibility of commutation of punishment and remission of crime don’t exist and judge must verdict similar to Islamic definite punishment. In contrast to indefinite punishment, the type and quantity of   definite punishment is determined in sharia. But the legislator of Islamic republic of Iran regarded the definite punishment for some crimes with discretionary punishment including Muharaba. So in spite of the crimes with discretionary punishment that can be diminished and remitted but this advantage has been impossible for this type of crime. The justification of Iranian legislator action is faced with the question.