Although the word "war" has a frightening appearance, in some cases it has a positive value and takes on an aura of holiness; because in some cases, human life and other creature survives through war with natural or human destructive factors, its laws and related matters have occupied the human mind in different periods of history. Therefore, this research aims to examine and explain the laws of war in international law in order to reduce the legal challenges of the army.This research is an applied in terms of purpose and a descriptive-analytical in terms of method. The tool for collecting information is a library study, and in this regard, existing books and articles in the field of war and international conflicts were reviewed and analyzed. The method of analyzing information was systematic, and finally, the sources of the laws of war in international law were identified. Explaining the characteristics of a lawful combatant in international law, determining military targets in international law, describing the characteristics of weapons in international law, identifying and classifying protected groups in international law, and explaining war crimes in international law are among the most important findings of the present research.The results of the research showed that the law of conflict should be developed as a cross-specialization course for commanders of operational units, a publication should be developed for this subject, and commanders and personnel of operational specialties should be trained in the course.