The research on using photovoltaic and energy storage in smart grids to support rail transit traction power supply has far-reaching scientific research significance and practical value. Based on the bidirectional conversion traction power supply device, this paper directly integrated the photovoltaic storage distributed power generation system into the DC traction network, which not only reduced the number of traction substation planning and design, but also saved the cost of the original photovoltaic storage inverter device, and achieved more efficient vehicle braking regeneration energy utilization. At the same time, this paper analyzed the application of photovoltaic storage system in new rail transit traction power supply, explored its technical advantages and implementation solutions, and ensured that the system can operate stably for a long time under photovoltaic and load fluctuations. Research showed that photovoltaic energy storage system can effectively improve the stability and reliability of rail transit power supply system, reduce energy consumption and carbon emissions, and achieve green and sustainable development of rail transit system.