The present invention discloses a frequency spectrum allocation method and apparatus for an overlapped multiplexing system, a storage medium, and a processor. The method includes: determining channel bandwidth for an overlapped multiplexing system, and obtaining first bandwidth for an overlapped multiplexing signal, where the first bandwidth is processing bandwidth for the overlapped multiplexing signal; obtaining second bandwidth other than the first bandwidth in the channel bandwidth for the overlapped multiplexing system; and allocating the second bandwidth to a non-overlapped-multiplexing signal. The present invention resolves a prior-art technical problem that bandwidth occupied by an overlapped multiplexing system is relatively wide but actual processing bandwidth is relatively narrow, causing a waste of frequency spectrum resources.