The invention provides a transmission coupling and a circuit breaker using the transmission coupling. The transmission coupling comprises two flanges fixedly assembled together through a coupling bolt, the two flanges are each provided with a shaft sleeve used for being coaxially assembled with a corresponding transmission shaft, the two flanges are provided with opposite inner side faces, the inner side faces of the two flanges are provided with protrusions and pits respectively, and the protrusions and the pits are arranged at intervals and used for increasing friction coefficients of the inner side faces. The opposite inner side faces of the two flanges are provided with the protrusions and the pits used for increasing the friction coefficients of the inner side faces so that friction force between the two flanges can be effectively increased, the inner side faces, attached to each other, of the two flanges can be used for transmitting large torque, and accordingly requirements for performance of the coupling bolt are lowered, relative rotation of the two flanges is reduced, and three-phase synchronism of the circuit breaker using the transmission coupling is improved.