A rail transit braking energy recovery system. The rail transit braking energy recovery system comprises a braking motor, a fuel battery, an electrolytic bath, and a hydrogen tank. The braking motor is used for converting braking energy of the rail transit into electric energy. An output end of the braking motor is connected to a power input end of the electrolytic bath. The electrolytic bath comprises a hydrogen output end and an oxygen output end, the hydrogen output end is connected to the hydrogen tank, and the hydrogen tank is connected to the fuel battery and is used for supplying hydrogen to the fuel battery. In the system, only the electrolytic bath is structurally added, and the existing vehicle-mounted hydrogen tank is directly used for storing hydrogen, therefore the structure is simple, the self weight of the vehicle body is reduced, the energy conversion efficiency is high, and at the same time, the injection of hydrogen is reduced and the operation cost is reduced. In addition, the purity of the hydrogen obtained by means of electrolysis is high, so that the hydrogen can be directly supplied to the fuel battery to be used without being processed. Also provided is a hybrid power rail transit system.