The invention discloses a signal receiving method for judging a transmission specification of an input signal and a relevant signal receiving circuit. The method comprises: the input signal is received; according to an output result of at least one of signal transmission channels, a signal detecting result corresponding to the at least one signal transmission channel is generated; and according to the signal detecting result, the transmission specification of the input signal is judged. The signal receiving circuit comprises an input interface, a detecting module and a judging unit; wherein, the input interface is used for receiving the input signal; the detecting module is used for generating the signal detecting result corresponding to the at least one signal transmission channel according to the output result of at least one of the signal transmission channels; and the judging unit is used for judging the transmission specification of the input signal according to the signal detecting result.