Most of the modern criminal legislation nowadays use the term (penal institutions) for the places which are allocated by the State to implement penalties of deprivation of freedom, which is often the nature of reform and rehabilitation of convicted persons in accordance with the personal circumstances of each of them. Therefore the aim of this study is to focus on the policy of treatment of prisoners in penal and correctional institutions. The policy based on the programs and methods of care , reform , discipline and rehabilitation of the inmate during the execution of the punishment to come back after that a citizen of honest good in the community rather than a person sliding into the abyss of crime. Also I Will shed light on how the international and national legislation bodies deals with the issue of methods of treatment of inmates in penal institutions. A researcher pursued in the writing of descriptive analytical research method adopted as a description of research and analysis of texts contained in the Oman Prison Act of the year 1998 and its Regulations. In addition to the comparison method which is based on the analysis and the interview between the opinions and doctrines and legal texts on international or comparative legislation. The research was divided into an introductory chapter and two main chapters. The first main chapters focus on the requirements to achieve the purpose for guests of the reformist penal institutions. The second main chapter dealt with methods of rehabilitation of inmates of the institutions punitive. The conclusion of the previous chapters discuss the most important of the findings and recommendations.