The invention relates to a preprocessing method, a preprocessing device and preprocessing encoding equipment, belonging to the technical field of encoding and decoding, wherein the preprocessing method comprises the following steps of: acquiring the characteristic information of a current frame signal, determining whether the current frame signal does not need to conduct encoding operation of removing long-time correlation according to the characteristic information of the current frame signal and preset information, carrying out encoding operation of removing short-time correlation on the current frame signal if the current frame signal does not need to conduct the encoding operation of removing the long-time correlation, and carrying out the encoding operation of removing the long-time correlation and the encoding operation of removing the short-time correlation if the current frame signal needs to conduct the encoding operation of removing the long-time correlation. The technical proposal of the embodiment of the invention can carry out the encoding operation of removing the long-time correlation on a part of input frame signals.