Abstract: In the background of development of rail transit energy internet, the potential and significance of photovoltaic（PV） application in AC/DC traction power supply system was firstly pointed out based on the distribution characteristics of traffic loads. Then, according to different power supply modes, the globe research status of AC traction power supply system was summarized, which include different phase（two phase） mode, co-phase mode, directly application in locomotives. And the status of DC traction power supply system was also summarized by integrating different braking energy recovery technologies, which include PV + energy consumption system, PV + energy feeder system, PV + energy storage system. Finally, the impact mechanism between PV and traction power supply system was analyzed from power quality, network voltage stability, load forecasting, system reliability, system protection, economical efficiency, etc. On this basis, further research focuses and suggestions were put forward to provide reference for promoting the construction of rail transit energy internet and broadening the commercial market research of PV de-subsidy.