The invention discloses a bus motor assembly, belonging to the technical field of motors. The bus motor assembly includes a casing, wherein a rotating shaft, a rotor that fixedly sleeves on the rotating shaft, and a stator that rotates with the rotor are arranged in the casing; one end of the rotating shaft penetrates out of the casing, and the other end of the rotating shaft is provided with a fan; a plurality of cooling channels are arranged in the rotor, a plurality of mounting grooves are evenly distributed on the surface of the rotor with intervals, cooling holes are formed in a part of the rotor located between two adjacent mounting grooves, a plurality of second cooling fins are arranged at one end of the rotor close to the fan, each second cooling fin is arranged around the periphery of the end surface of the rotor, and the end part of each second cooling fin is bent towards the direction far away from the central axis of the rotor; an annular partition plate is fixed on the inner wall of the casing, a plurality of third cooling fins are arranged on the inner side of the annular partition plate, and the end parts of the third cooling fins are bent towards the direction faraway from the fan. According to the bus motor assembly disclosed by the invention, the heat dissipation performance of the motor can be improved, and the motor can be used in a high temperature environment.