A transmission cable is provided to implement high-speed inter-device interconnection and intercommunication. The transmission cable includes a positive dispersion transmission section, a negative dispersion transmission section, and a dispersion matching section. A cross-sectional diameter of the positive dispersion transmission section is less than a cross-sectional diameter of the negative dispersion transmission section. The dispersion matching section is configured to connect the positive dispersion transmission section and the negative dispersion transmission section. The transmission cable can implement dispersion cancellation to reduce total group delay.