Abstract: The penetration rate of renewable sources in power system increases gradually,system inertia decreases apparently and response characteristics of frequency changes greatly which brings serious challenges for operation and control of power system. Based on renewable power system of new generation which contains virtual synchronous generator control strategy,all kinds of inertia resources are analyzed in detail from the perspectives of both theoretical inertia and calculated inertia. Besides,an original method to estimate system inertia accurately is proposed considering photovoltaics. Then power system simulation model is conducted based on DIgSILENT PowerFactory. Considering scenarios of traditional power system and photovoltaics integration,system inertia are precisely evaluated.Simulation results demonstrate that the proposed strategy exhibits good feasibility,effectiveness and accuracy for both traditional power system and renewable power system.