The invention discloses a communication cable extension method and in particular relates to the technical field of short distance wire communication. With the adoption of the method, software and hardware of a communication host end and a peripheral end does not need to be changed, and signal extension and bidirectional transmission are realized by installing a control drive module in a cable. An extension cable comprises an upstream port, an upstream cable section, an upstream control drive module, a middle extension cable section, a downstream control drive module and the like. The core of the extension cable is the control drive module which comprises a control circuit, a signal receiving drive circuit, a power supply circuit and the like. Under an idle condition, a drive circuit can be unidirectionally driven to a downstream port by the control circuit, and meanwhile the control circuit is used for judging the transmission direction of a next data package according to a received data package. If the next data package is the data received by the upstream port, the drive circuit can be unidirectionally driven to the upstream port by the control circuit, and otherwise the drive circuit can be maintained to be unidirectionally driven to the downstream port, so that the bidirectional extension transmission of data communication is realized.