The issue of terrorism is one of the most important issues discussed among countries in the world, because its consequences in security, political, legal, economic, military and even cultural issues have always been tangible and effective. In this regard, different countries in the world have adopted and implemented different approaches and policies in combating the financing of terrorism based on the necessity of combating and confronting terrorism. Accordingly, the purpose of the present study is to examine preventive approaches in combating the financing of terrorism; a comparative study of the policies of the Islamic Republic of Iran and international documents. The main question is: "What are the preventive approaches of the Islamic Republic of Iran in combating the financing of terrorism based on international documents?" The findings of the research, using a descriptive-analytical method, library resources, and terrorism theory, showed that the preventive approach of the Islamic Republic of Iran in combating the financing of terrorism is based on two types of criminal and non-criminal prevention, while in international documents on this issue, it is of the type of non-criminal prevention. Accordingly, the laws existing in Iranian law regarding the fight against the crime of financing terrorism are of the type of criminal prevention, and environmental, social, and managerial factors are also of the type of non-criminal prevention, although the lack of a comprehensive and complete concept and elements of terrorism has created legislative challenges in this regard.