Today, the importance of cultural and social factors and their impact on all aspects of human life, including religion, is obvious to everyone. Mazandaran, a province in Iran, is also an ancient land that has faced different cultures in different ages, the most important of which is the Shiite school, as the emergence of Shiism in the east part of the Islamic Caliphate in the first centuries happened with the presence of the Alevi Shiite school. This study by examining the factors of the formation of Shiism in Mazandaran is going to answer the basic question, "Which cultural and social factors have been effective in expanding and stabilizing Imᾱmῑ Shiism in Mazandaran?" The research method is descriptive-analytical and data collection has been done using library resources. In conclusion, cultural factors such as the activity of Shiite scholars, the role of writers and poets, the convergence of Sufism with Shiism, respect for Sᾱdᾱt (those who are in the lineage of the Prophet Muhammad), art, architecture and religious places, in addition to social factors such as the social function of shrines, holy tombs and common religious rituals, have been effective in the expansion of Imᾱmῑ Shiism in Mazandaran.