Abstract: The main advantage of a 3D real-time MCSEM monitoring system is its characteristics of real-time. Displaying the construction process with 3D visualization methods in real-time contributes to avoiding abnormities through monitoring and analyzing the work process. This paper develops a real-time dynamic update method to deal with 3D scenes. The method bases on the practices and procedures of MCSEM, and is implemented with the OSG 3D rendering engine, including the real-time updates of 3D models, the plotting of topographic features like the seabed topography and trace, and the real-time tracking of cameras. In addition, this paper contributes to the scene rendering optimization by studying the data structure and rendering mechanism of 3D scenes. The scene rendering optimization mainly results in the improvement of responding rate and the real-time and fluency of 3D display. Furthermore, an advanced 3D real-time monitoring system is implemented and further verified to meet the requirements of real-time monitoring.