Abstract: In the power system with high penetration electronic devices, parts of synchronous machines were replaced by large-scale renewable energy and DC transmission. The system inertia has changed in characteristics and form. The traditional inertia response system and analysis methods are facing challenges. In this paper, the impact of power electronic devices integration on the system frequency dynamic process was described based on the frequency response mechanism of traditional synchronous system. Aiming at the complex inertia response characteristics of power system with high penetration electronics, the concept of synchronous generator inertia was extended and generalized inertia definition of power system was proposed in this paper based on the physical properties of inertia to resist the frequency change of the system. Different forms of inertia were combed and classified from system levels, which formed the generalized inertia response and analysis method for power system of high penetration electronics. Finally, the impact of renewable energy on system frequency was introduced and the generalized inertia level of future system was deduced, which laying the foundation for the frequency stability research of power system with high penetration electronics.