The optical storage microgrid system composed of power electronic converters is a small inertia system. Load switching and power supply intermittent will affect the stability of the direct current (DC) bus voltage. Aiming at this problem, a virtual inertia optimal control strategy applied to optical storage microgrid is proposed. Firstly, a small signal model of the system is established to theoretically analyze the influence of virtual inertia and damping coefficient on DC bus voltage and to obtain the constraint range of virtual inertia and damping coefficient; Secondly, aiming at the defect that the Sailfish optimization algorithm is easy to premature maturity, a Sailfish optimization algorithm based on the leak-proof net and the cross-mutation propagation mechanism is proposed; Finally, the virtual inertia and damping coefficient of the system are optimized by the improved Sailfish algorithm to obtain the best control parameters. The simulation results in Matlab/Simulink show that the virtual inertia control optimized by the improved Sailfish algorithm improves the system inertia as well as the dynamic response and robustness of the DC bus voltage.