Defense diplomacy is a part of the national power of countries, which, along with foreign policy, forms the source of exercising power to enhance a country's capacity for action and action in foreign relations. The priorities and goals of foreign policy of countries are directly a function of internal structures, including geopolitical conditions, domestic needs, national power and security threats, the attitude of the ruling elites, and the quality of the structure of the international system. The Republic of Tajikistan is no exception to this general rule. Tajikistan also enjoys cultural, religious, historical, linguistic, scientific and technological commonalities and other factors affecting convergence with Iran. Therefore, based on geopolitical and geoeconomic realities, it is natural and logical for Iran to give strategic attention to the security developments and challenges in Tajikistan. This research is of an applied and developmental type and has been conducted in a descriptive-analytical method with a mixed approach. The statistical population of this study was purposefully estimated at 60 people and the sample population was selected according to the statistical population and in full. Data analysis was done using content and discourse analysis methods, and the Lavosh coefficient was used to measure the validity of the questionnaire and Cronbach's alpha was used for its reliability.