Since ancient times, the land of Iran has housed various ethnic groups and these ethnic groups have had a peaceful coexistence with each other despite having different languages, rituals, tastes and dialects. Considering the ethnic and linguistic diversity of Iranians, it is necessary to strengthen empathy and common language among the members of the Iranian nation in order to confront the enemies, and inciting ethnic differences should be strictly avoided. Considering this importance, national unity and cohesion is always under threat and it is necessary to deal with these threats and maintain national unity by using available mechanisms and tools and by adopting an effective criminal policy. Due to the importance of ethnic cohesion and national unity, a variety of criminal policies (legislative, executive and judicial measures) have been adopted in Iran's legal system to deal with actions that disrupt national unity and ethnic cohesion. It has been explained. Among the manifestations of Iran's legislative criminal policy in order to preserve national unity, we can mention the criminalization of behaviors such as insulting ethnic groups, inciting people to kill and fight with each other, and promoting racial discrimination considered.