The embodiment of the invention discloses a signal classifying method, a classifying device and a coding system. The signal classifying method comprises the steps of: obtaining an inputted high-frequency band input signal; confirming the signal type of the high-frequency band input signal according to the time domain characteristic parameter and/or the frequency domain characteristic parameter ofthe obtained high-frequency band input signal; and confirming the coding mode of the signal type. The classifying device comprises a receiving unit and a processing unit, wherein the receiving unit is used for obtaining the inputted high-frequency band input signal, and the processing unit is used for confirming the signal type of the high-frequency band input signal according to the time domain characteristic parameter and/or the frequency domain characteristic parameter of the obtained high-frequency band input signal and confirming the coding mode of the signal type. The embodiment furtherprovides a coding system. The technical scheme of the invention can well subdivide and process the high-frequency band input signal to be better for coding and decoding the signal.