The development of contemporary electrical power system causes the frequency characteristics more intricate and makes frequency stability more significant. Therefore, power system frequency problems is more and more significant, research on system frequency characteristics emerge and are applied to make system work more securely and steadily. Firstly, it reviews the process and causes of domestic and overseas frequency events in recent years from perspective of frequency dynamic characteristics. Then, combined with the characteristics of modern power system, the impacts on the frequency characteristics of large-scale power electronic interface are analyzed from multiple perspectives. After that, utilizing the single machine model to analyze the influence of generator parameters on multiple interactions of power system frequency dynamics, and summarize the related research and application of system inertia estimation, frequency regulation performance and frequency dynamic characteristics monitoring. Finally, some problems and directions worthy of exploration and research in the field of system frequency characteristics are proposed.