Abstract: With the increasing penetration rate of renewable energy in power system,the system ability of supporting frequency is getting worse and worse. Configuring virtual inertia for power system is an effective way to solve this problem. To effectively allocate the virtual inertia,the Voronoi diagram interpolation method is proposed to optimize the virtual inertia distribution. The mathematical model of virtual inertia in power system is established. The stability of the system is judged by Lyapunov direct method and the 2-norm of the decision matrix is used as comprehensive evaluation performance indicators. The stability of the system frequency is analyzed when multiple influence factors interact. The Voronoi diagram and center of gravity interpolation method is used to find the optimal solution of the inertia. The optimization results are verified by simulation. Compared with other traditional methods,simulation results show that the virtual inertia is configured based on the method. The result is more accurate and the calculation speed is faster,and it could use virtual inertia more effectively to improve system frequency stability.