Game theory, applied in various fields, including in law, studies conflict game models and searches for their formatted solutions, makes it possible to solve many tasks and problems, predict the behaviour of subjects in various situations, thereby explaining the behavior logic of the individuals in conflict of interests. However, human behavior is not always rational (reasonable), moreover, it can be difficult to predict which strategy the player will choose when making his move in the game. In this regard, it is advisable to consider rational behavior as an accepted and reasonable behavior of game participants and irrational behavior as deviant, unpredictable behavior of players, which relies on the internal regulation of a person (beliefs, intuition, creativity, feelings, emotions, etc.) and which studies one of the developing directions of game theory in modern science – evolutionary game theory. The study aims to determine the types of irrational behavior of players, which puts other players in a difficult position and precludes from determining each other’s optimal strategies for mutual benefit and stability, using the example of legal incidents modeling through games with imperfect rationality. The authors believe, that to achieve this goal using the methods of analysis and modeling, the imperfections of rationality can be considered and studied, the types of irrational behavior of players can be defined using the games with imperfect calculation of the game, imperfect information and changes in goals during the game (with a multipersonal representation of the game) and a complete absence of rationality.