The computer graphics and visualization methods are increasingly used in the field of simulation to provide presentation possibilities of the simulation results and to speed up the execution of verification and validation tasks for the simulation models. The rapid progress in computer graphics technologies enables the development of ever more complicated and realistic visual depictions of the modelled systems, at the same time additionally postulating the existing simulation solutions and creating the necessity for new approaches and methods in the integration of simulation and visualization. This thesis describes the research results of simulation and visualization integration that are obtained through solving such topical problems as providing a user interactivity during the simulation execution, as well as simulation and visualization synchronization and ensuring interoperability during the simulation of combined discrete event and continuous systems. The work provides an analysis and justification of usage and advantages of the system approach based discrete event system specification (DEVS) with the purpose to determine major drawbacks of the existing visual simulation systems and to determine general requirements to an integrated visual interactive discrete event and continuous systems simulation environment. A comparative analysis of visualization approaches and methods for their integration in the simulation is performed as well. Based on the performed research, a new system theoretical formalism for an integrated visual simulation of discrete event and continuous systems is developed within the framework of this work that is realized in the form of a software prototype. The underlying concepts of the developed software system are laid out; implementation details and evaluation results are discussed. The practical importance and application possibilities of research results are demonstrated by developing a simulation model of an automated manufacturing system and executed simulation experiments. The main results of the thesis have been presented at 8 international conferences, as well as they are reflected in 7 scientific papers. The thesis includes introduction, 4 chapters and conclusions. It contains 127 pages, 66 figures and 16 tables in the main text, 4 appendices and 123 titles in the bibliography.