A ventilating duct structure of a stator core comprises a plurality of repetitive structural units, wherein each repetitive structural unit is formed by a channel which is defined by an upper ventilating slot piece, a lower ventilating slot piece and two adjacent ventilating duct supporting components; one end of each ventilating duct supporting component is connected with the upper ventilating slot piece, and the other end of each ventilating duct supporting component is connected with the lower ventilating slot piece; the upper ventilating slot piece or the lower ventilating slot piece is provided with at least one protuberance which extends in the radial direction of the stator core; the protuberance is positioned in the channel; the protuberance of the upper ventilating slot piece and a stator core fan-shaped piece adjacent to the upper ventilating slot piece define a ventilating path; the protuberance of the lower ventilating slot piece and a stator core fan-shaped piece adjacent to the lower ventilating slot piece define a ventilating path; the protuberances divide the channel into a plurality of ventilation and heat exchange spaces. By improving the ventilating duct structure of the stator core, the cooling effect of a stator is remarkably improved, the flow of cooling gas and loss of ventilation are also greatly reduced, and accordingly, the efficiency of a motor is improved.