With the advancement of the criminology science and a penology development in the past, imprisonment was the center of the criminal justice and during the last two centuries, imprisonment of the criminals has been changed into the most common political and criminal response to the crime phenomenon. On the other hand, the criminal inflation of prisons and its damages has caused many problems and difficulties for the society, prisoners and their families as far as using prison's alternative punishments have been focused by criminologists, penologists and other different social and judicial authorities. Imprisonment not in prison, as one of the prison's alternative punishments, has been anticipated in the recent procedural and substantial criminal laws of Iran which is required to be analyzed and discussed.