One of the important topics in the studies of Iranian political history is the study of the correspondence of Iranian politicians, diplomats, and ambassadors. In different periods of Iranian history, numerous examples of this correspondence have been written with different motives in the field of political, cultural, and commercial relations with foreign governments. In addition to showing the character and political vision of Iranian politicians, the study and content analysis of such correspondence also reveals the policy and strategies of foreign relations of the period under study. Considering the importance of political correspondence and its place in the studies of foreign relations, the following article focused on the study and analysis of the correspondence diplomacy of Shah Abbas I. This fundamental research, which has been developed using a descriptive-analytical method, attempts to analyze the writing style and speech logic of Shah Abbas I in his political correspondence, as well as to examine his function in foreign relations during the Safavid period. The findings of this research show that Shah Abbas I adopted different positions in his correspondence diplomacy towards Muslim Emirs and European politicians, and these differences is obvious the authoritative tone based on the Shah's ideological distinction towards Muslim Emirs and his moderateness and tolerant positions towards Europeans.