Despite the nomadism of the Mongols and their lack of attendance, they were considered one of the peoples that dealt with the widest range of peoples who were considered the most civilized, including the Chinese and the Turks in Transoxiana, Turkestans, Iranians, the peoples of the Caucasus, Arabs and Europeans as well as the Koreans and the peoples of Indochina, and they showed that their ability is superior in fighting and occupying their countries, and the policy of ruling the peoples of these countries from which their empire was formed, it is not reasonable for them to achieve these accomplishments without having strict systems and laws and a government and an army based on coherent systems, these systems and laws that Genghis Khan called the Yasa law and the administrative system of his government The army and the principle of dividing the inheritance of its empire among its family members is the subject of this study.