Humanitarian law is one of the most important issues of the contemporary world, and is one of the great achievements of the 19th and 20th centuries in the international legal system. Its support and its promulgation, after the approval of world leaders at the global level, were popular and international institutions. Support for civilians, such as prisoners, wounded, sick, fugitives, women, children, elderly, and respect for dead bodies, and the prohibition of famine and starvation of the military and civilians and the use of illicit weapons, including the rules and practices of law They are humanitarian outbreaks of conflict and conflict. In this research, we have tried to investigate the above from the thoughts of Imam Ali (AS) with the focus of the Nahj-ol-Balagha book. In general, Imam Ali (AS), both in the early days of Islam and during his governor in the wars of Jamal, Siffin and Nehravan, despite his thought of inviting to peace, paid close attention to the observance of the rights of even civilian and non-civilians, Attention did not cause damage. Although some of the humanitarian law that is mentioned in international documents under different titles and names does not explicitly refer to the same as in the words of the imam, but with the prioritization and unity of criterion, there are some recommendations and the behaviors of Imam (AS) are inferred.