Abstract: The substation secondary system undertakes the tasks of protecting, controlling, measuring and monitoring of the power grid and its equipment in order to realize the real-time collection and delivery of the data and information about operating, alarming and monitoring, which is crucial to ensure the safe and stable operation of the power system. This paper summarizes the technical characteristics of several main development stages of Chinese substation secondary systems and the construction experiences of the intelligent substation secondary systems in recent years, and analyzes the shortcomings of the secondary systems at the present stage. By analyzing the factors that may promote the technical progress of the secondary systems, some new developing ideas are put forward from the aspects of the second system structures, the monitoring enhancement, the reliability improvement of the functions and the security defense. In terms of the second system structures, emphasis is laid on the optimization schemes of the whole station, such as the efficient and reliable data collection, the optimization and integration of the equipment functions, the communication network deployment and implementation, and the improvement of the SCD application level. As for the monitoring enhancement, from the angle of satisfying the equipment monitoring and its convenient operation and maintenance, the integrated monitoring scheme of the main and auxiliary equipment is put forward, and the architecture combining the general platform with the open application function of the monitoring system is illustrated. For the reliability improvement of the system functions, some measures are presented, such as improving the reliability of the whole protection system, the ability of the wide-frequency measurement, and the ability of early warning and high concurrent data processing. As to strengthening the ability of security defense, on the basis of the established boundary protection system, a scheme to consolidate the endogenous security of equipment is proposed To realize the wireless security access of a variety of new sensor information while ensuring the substation information security. The State Grid Corporation of China will carry out the application practice of the above technical schemes, and constantly summarize and improve them in the construction applications.