Disclosed are a tramcar power system and a method for controlling the system, the system comprising: a fuel cell (11) coupled to an unidirectional direct-current converter (14); a super capacitor (12) coupled to a first bi-directional direct-current converter (15); and a power battery (13) coupled to a second bi-directional direct-current converter (16), wherein the unidirectional direct-current converter (14), the first bi-directional direct-current converter (15) and the second bi-directional direct-current converter (16) are coupled to an inverter (18) via a direct-current bus (17); the inverter (18) is coupled to a motor of the tramcar; the fuel cell (11), the super capacitor (12), the power battery (13), the first bi-directional direct-current converter (15), the second bi-directional direct-current converter (16) and the inverter (18) are coupled to a master control unit (19); and the master control unit (19) is coupled to a controlling device of the tramcar.