The invention discloses a low-energy-consumption and maintenance-free circulating fluidized bed boiler slag cooling machine and relates to a boiler auxiliary facility. A barrel is fixed on a base through supporting bearings at the two ends and connected with a retarding mechanism through a driving motor; multiple round rollers with inner spiral baffles inside are distributed inside the barrel; the base (1) is formed by welding square steel and I-shaped steel; bolt holes are formed in the base; two ends of the base are taken as the lower half part of a supporting bearing (2); the supporting bearing (2) is also provided with an upper half part; the lower half part and upper half part of the supporting bearing (2) are combined together; the barrel is arranged at the central position of the supporting bearing (2); a circular pipe is arranged in the barrel (5); an inner spiral baffle is welded in the circular pipe; a space transition section is arranged at each of the slag inlet (4) and the slag outlet (8) of the barrel; the slag inlet (4) is provided with a circular pipe; the slag outlet (8) is arranged at one side of the driving motor (6) and a cooling water inlet (9) is arranged at the side of the driving motor (6) and the slag outlet (8). According to the invention, electric energy can be saved by 30-40%, easily-damaged parts are not used, investments of accessory equipments of the slag cooling machine are reduced and the cleaning of the inside of the cooling machine is guaranteed when the cooling machine is not in operation.