Urban diplomacy is one of the new concepts in the field of diplomacy. This concept refers to the presence of cities along with governments, NGOs, multinational corporations and international organizations as well as other international system actors in international interactions. Metropolises, as the largest human collections in the world, have a huge share in expanding and exploiting urban diplomacy. In other words, metropolitan cities can play a role in the field of diplomacy, in a coordinated manner with countries in this area. Hence, metropolitan areas such as Mashhad, with their unique geographical, religious, economic, cultural, and scientific and communication potential, are of great importance in Iran's diplomatic mobility and engagement with its counterparts and regional organizations such as the ECO. This paper seeks to answer the question that the potential and potential components of the metropolitan macro city role in the field of urban diplomacy, with a view to the geographic area of the ECO Economic Cooperation Organization, is that in Mashhad's opinion, and in a sense Khorasan has more natural, human, and semantic features than other cities in the ECO. The method used is a library and field method (questionnaire).