In view of the common high energy cost problem of the enterprise optical storage system, considering the influence of the correlation of photovoltaic output, load demand and peak valley time-sharing price on the optical storage capacity allocation in different periods, based on the peak valley time-sharing price and storage state information, the system operation strategy and capacity allocation principle are determined based on the actual size of photovoltaic output and load. Based on the cost and benefit of each component, capacity allocation model with the lowest energy cost as the objective is established. The genetic algorithm is used to solve the optimization problem, and the optimal allocation capacity and operation strategy of optical storage are obtained. The validity of the model is validated by an example. In addition, the sensitivity analysis of the system shows that the future optical storage system planning can also select the appropriate capacity optical storage combination according to the change of time-sharing price and energy storage investment cost, which has practical engineering value.