Abstract: The scientific evaluation and calculation of the power supply capacity of DC power distribution system containing green energy has become a key part of the fine evaluation and planning of urban power grid. In view of this demand, a method for analyzing the power supply capacity of DC distribution network is proposed. Taking N-1 safety criterion as the boundary condition of system operation, the calculation method of power supply capacity of DC distribution system is analyzed considering the power supply capacity of converter station and the power transfer capacity of the grid. Based on this calculation method, the influence of the access of the integrated optical storage power station on the power supply capacity of the DC distribution network is studied, and then how to configure the energy storage capacity in the same optical storage power station and among several different optical storage power stations to maximize the power supply capacity of the DC distribution network is studied. Finally, the effectiveness of the proposed analysis method is verified by calculating the power supply capacity of a group of DC distribution network topology cases. The simulation results provide a theoretical basis for the planning, evaluation and design of DC distribution network of integrated power station with optical storage.