The article investigates the formal models as a method of analysis in international studies. The importance of this type of models in writing articles for world leading high-ranking journals from Scopus list is shown. The author reveals the main challenges of interdisciplinary synthesis related to the construction of formal models. The problem of identifying the actors of international relations is revealed, including the assessment of actor’s involvement in a concrete international conflict (or process) in the context of the concepts of defensive and offensive realism, as well as of real and of latent (potential) power. The decrease in the influence of the state as the primary actor in international relations, and the increase of influence of new types of actors are shown, including international terrorist networks (led by IS), political parties, media and NGOs in the context of post-modernism, global business structures. At the national level, the main actors are illustrated both by the example of countries with a developed civil society and a market economy, and by that of the traditional non-Western society. The question of levels of analysis in international relations, as well as agent-structure problem are illustrated by concrete cases from modern international relations. The author describes a model of “nested” politics. The main types of models used in international studies (game theoretic, econometric, network analysis, simulation) are indicated as well as their shortcomings. Two kinds of simulation models – system dynamics and agent-based modeling are described. It is noted that the agent-based modeling is carried out mainly in the framework of the constructivist paradigm of international relations theory.