Disclosed is a method and an apparatus for incremental upgrade. When a server generates an incremental file, it acquires sub-files of different types in an old version compressed file and a new version compressed file, and performs different difference comparison steps on the sub-files of different types, to obtain difference data files for corresponding types: for sub-files that satisfy a preset decompression condition, a decompression comparison method is used to perform difference comparison, and for sub-files that do not satisfy the preset decompression condition, a direct comparison method is used to perform difference comparison; subsequently, a client acquires the difference data files from the server, and according to the type of a difference data file, carries out a merge operation on the difference data file and the old version compressed file to obtain the new version compressed file.