A compression system includes at least one acceleration device, a memory of the acceleration device stores a compression library, and the compression library includes one or more compression algorithms that support implementation of a lossless compression mode. The lossless compression mode is split into one or more fine-grained compression algorithms. Therefore, when obtaining any compression request, the compression system may select, based on an identifier that is carried in the compression request and that indicates a lossless compression mode, a compression algorithm corresponding to the lossless compression mode, thereby performing compression processing on data in the specified lossless compression mode by using the compression algorithm corresponding to the identifier.