In the introduction to this study the author points out that research into the problems of modelling educational objects is topical because researches are being prepared within the framework of the state and departmental plans in the Czechoslovak Socialist Republic. He goes, on to explain the significance of modelling as a multi-functional method of scientific investigation in the social sciences in general, and in pedagogy in particular, and to underline its importance in developing structured system researches, and its role in making prognoses of the development of educational phenomena. In the study the author analyses the notion of model (modelling) and defines the main principles of model-making. He goes on to evaluate the development, present day state and problems of modelling in pedagogy, paying attention especially to the gnoseological problems of modelling. In another part of the study he deals with the character, levels and types of models, whose application in the researches on the main item of the state plan — the System of Lifelong Communist Education in the Czechoslovak Socialist Republic — is under consideration. In the concluding part of the study the author mentions some questions concerning the actual technique of model-making with regard to the results achieved in carrying out the planned research tasks in the 1971—1975 period.