The study, taking into account the historical urban planning principles of Saint Petersburg and the existing problems of maintaining the integrity of the ensemble of its historical center, determines the need for a special study of the urban planning compositional system of the historical center of Saint Petersburg and reveals its features in comparison with the systems of historical centers of Venice, Amsterdam, London, Paris and Rome. A graphical comparative analysis was carried out on the basis of historical fixation plans and developed graphic models of urban planning and compositional systems of cities. It was determined that the vast majority of the compositions of the historical center of Saint Petersburg are regular, the ensemble is characteristic of the entire territory of the historical center of Saint Petersburg, the scale of the integral ensemble of the historical center of Saint Petersburg significantly exceeds the parameters of the historical centers of European cities.