The paper develops a cyber physical system (CPS) security platform for supporting security countermeasures for digital energy systems based on real-time simulator. The CPS platform provides functions that trainers or trainees can be able to operate and test their scenarios with a state-of-the-art integrated solution running at a real-time simulator. Those integrated solutions include energy systems simulation software and communication systems simulation/emulation software. The platform provides practical “hand-on-experiences” for participants and they are able to test, monitor and predict behaviors of both systems at the same time. The platform also helps achieve training’s objectives that meet skilled requirements for the future generation in both smart energy systems evaluation and cyber physical security fields. In particular, we present the CPS platform’s architecture and its functionalities. The developed CPS platform has also been validated and tested within different simulated threat cases and systems.