Today, coercive criminal policy and harsh punishments and intimidation have been replaced by friendship, adjustment and flexibility. Perhaps the reason for removing the death penalty (as an illegitimate child of royal governments) and turning to the deprivation of liberty (imprisonment) can be seen as the result of not fulfilling the goals of punishments, the usefulness and rehabilitation of criminals. In the beginning, the substitution of imprisonment for severe corporal punishment was very promising. The unfavorable use of custodial punishment turned this hope into despair. As of December 2021, nearly 11.5 (eleven and a half) million people are in prison around the world, according to research by the Department of Criminal Justice and Criminal Policy! Therefore, criminal justice policymakers tried to provide strategies and policies to reduce the criminal population of prisons. This caused the emergence of new strategies in societies, including the American First Step Act. The present article, with a descriptive-analytical method, aims to analyze the strategies of the above-mentioned law and the feasibility of its application in Iran's legal system. The research results showed that; Some strategies of this law, such as "risk assessment system, rehabilitation of prisoners, use of more facilities for prisoners, changing the status and serving the sentence outside of prison" are in accordance with the current policies of Iran and with their application, it is an effective strategy in reducing The prison population is considered criminal.