A signal classification processing method, a classification processing device, and an encoding system are provided. The signal classification processing method includes: obtaining a high band input signal; determining a signal type of the obtained high band input signal according to a time domain characteristic parameter and/or a frequency domain characteristic parameter of the high band input signal; and determining an encoding mode corresponding to the signal type. The classification processing device includes: a receiving unit, configured to obtain a high band input signal; and a processing unit, configured to determine a signal type of the obtained high band input signal according to a time domain characteristic parameter and/or a frequency domain characteristic parameter of the high band input signal and determine an encoding mode corresponding to the signal type. An encoding system is also provided. Therefore, type subdivision and processing are performed on the high band input signal, so as to facilitate encoding and decoding processing of the signal.