In large-scale photovoltaic grid-connected systems, multiple virtual synchronous generator (VSG) units are often used to coordinate and provide virtual inertia for the grid. However, the unreasonable distribution of virtual inertia will lead to poor system frequency response and source-end vulnerability in actual operation. To solve this problem, this paper proposes an inertia coordination control strategy for hybrid optical storage multiple VSG cells. By using the membership function, the strategy converts three indicators of the state of charge of the energy storage unit, i.e., the adjustable power of the converter and the adjustable power of the energy storage charge and discharge, into the same dimension, so as to solve the problem of multi-objective conversion in the moment of inertia distribution. At the same time, the parameters in the membership function can be flexibly adjusted according to the index characteristics to adapt to the inertia distribution under different working conditions. By establishing a small signal model of six-terminal AC system, the root locus method is used to analyze the stability of the dominant parameters in the membership function, and then to determine the parameter selection range. The optical storage six-terminal AC system model was built in MATLAB/SIMULINK and the time domain simulation was carried out. The simulation results verified the effectiveness of the proposed control strategy.