A method and an apparatus for installing and updating software are provided. The method includes: establishing a first directory corresponding to a current version of software in a pre-defined directory, placing a resource file of the current version of the software in the first directory; searching the pre-defined directory for a directory corresponding to a latest version of the software when a main program of the software is started, and loading the directory corresponding to the latest version of the software; downloading and installing a new version of the software when the software is running, establishing a second directory corresponding to the new version of the software in a directory where a directory corresponding to an old version of the software is stored, and placing a resource file of the new version of the software into the second directory. The apparatus includes: an initial installing module, a main program file and an update process module. Various embodiments of the present disclosure implement quiet update of software, reduce the amount of human-machine interactions during an update process, and make the software easier to use by users.