The South Caucasus region is of strategic importance for the Islamic Republic of Iran due to its geo-economic capabilities and geo-political location. Therefore, any action and factor by its regional and extra-regional actors that leads to a change in the geography of the region can affect Iran's geopolitical advantages and change the balance of power to its detriment. This research analyzes the formation of the Zangzo corridor and its effects on Iran's geopolitics with descriptive-analytical method. The results of the research show that in the case of the superiority of Azerbaijan and the realization of the Zangzor Corridor, along with the geographical and geopolitical changes of the region, it will have political, economic and security consequences for the country of Iran, which will affect the future of the country's geopolitical position and is one of the advantages of Iran's superiority. It reduces in favor of competitors in the region and the international environment. On the other hand, this region can become an arena for the presence of extra-regional forces that are rivals and enemies of Iran. And these can prevent Iran from its geopolitical and geoeconomic goals in achieving a safe and balanced region in the South Caucasus. Therefore, the Zangzor Corridor can be a prelude to the threat to the security and national interests of Iran, which necessitates the strategic decision of the Islamic Republic of Iran to prevent the closing of the historical border between Iran and Armenia.