On the platform of substation integrated supervision and control system based on operation smart system of China Southern Power Grid, a complete substation secondary simulation system is designed and realized. The scheme of system is designed in detail, and the main technique characteristics of simulation system are elaborated, and the realization and application of system is introduced. The simulation system can simulate a lot of substations, and can execute many simulation tests flexibly and efficiently including all kinds of static tests, dynamic test and avalanche test, etc., without relay protection. The simulation system’s data is fully coupled with substation. It can be applied for training, debugging and repeated accidents and master assessment with low implementation cost.