The invention discloses an electric centrifugal fan for air supply. The electric centrifugal fan for air supply comprises a fan device, an impeller part for generating air currents through rotation, and a motor; the motor is connected with the impeller part, and the impeller part is rotated around a center shaft Z1; the motor is an outer rotor motor; the motor is provided with a stator part as a fixed assembly body, and a rotor part as a rotary assembly body; and the rotor part is supported by a bearing mechanism, and can rotate corresponding to the stator part with the center shaft Z1 as center. The impeller part can be firmly mounted on a yoke; the damage of the impeller caused by heat deformation can be prevented; the fixing mode between a traditional rotating shaft and the inner side surface of a cylinder part of the central part of the yoke is changed; and the rotating shaft is firmly mounted on the inner side surface of the cylinder part of the central part of the impeller to meet actual use requirements.