In smart grid and energy internet, the security and stability control of power system are impacted seriously by factors such as the reliability of communication network and its latency and bits errors. This paper first gives a review of the current status of the research on hybrid simulation of power system and communication network. After analyzing the characteristics and the dynamic features of SDH (synchronous digital hierarchy) network which supports the power system protection and stability control functions, the framework and key technologies for power system and communication network hybrid simulation platform is proposed, and an interactive hybrid simulation platform for power system and communication network is developed with FASTEST (a power system simulation software) and SSFNET (a communication simulation software) to study the impact of communication failures on the stability control devices. Finally, the impact is verified with the platform on a case of certain provincial power grid.