The main purpose of the article is to identify the main problems of European integration in building the EU security policy in the context of countering terrorism. The research methodology includes the methodology of graph and connection theory. Taking into account the opinion of experts, the main problems of European integration in building the EU security policy in the context of countering terrorism for the countries of Eastern Europe were identified. After the start of a full-scale invasion of the russian federation into the territory of Ukraine, a large number of countries that are not yet members of the European Union have stepped up and are striving to start integration processes to form a common European security system. In this regard, the purpose and content of this study are to more thoroughly define these processes and identify the main problems and issues. As a result of the study, the main problems of European integration in building the EU security policy in the context of countering terrorism were identified. The main model of the negative impact of the key problems of European integration in the construction of EU security policy in the context of countering terrorism was formed. The study has limitations and deals with taking into account the specifics of security policy exclusively in the countries of Eastern Europe. Further research is needed to determine the main problems of European integration in building the EU security policy in the context of countering terrorism for the countries of the world.