An application software installation method, comprising: accessing (301, 401), by a device (200, 500, 700), a server (110, 600, 800), wherein the accessing (301, 401), by a device (200, 500, 700), a server (110, 600, 800) comprises: accessing, by the device (200, 500, 700), the server (110, 600, 800) by logging in to an associated account, wherein the associated account corresponds to a to-be-installed application set; after the accessing, by the device (200, 500, 700), the server (110, 600, 800) by logging in to an associated account: if third application software not belonging to the to-be-installed application set has been installed in the device (200, 500, 700), sending, by the device (200, 500, 700), an adding request for a third application software identifier to the server (110, 600, 800), wherein the third application software identifier indicates the third application software, so that the server (110, 600, 800) adds the third application software identifier to the to-be-installed application set based on the adding request; receiving (302, 402), by the device (200, 500, 700), an editing operation of a user for the to-be-installed application set in the server (110, 600, 800), wherein the to-be-installed application set comprises N application software identifiers, wherein N is a positive integer, the N application software identifiers are used to indicate corresponding to-be-installed application software, and the to-be-installed application software is application software backed up by another device in the server (110, 600, 800); and sending (303, 403), by the device (200, 500, 700), an editing instruction for the to-be-installed application set to the server (110, 600, 800) based on the editing operation, wherein the editing instruction is used to instruct the server (110, 600, 800) to add (304, 404) an application software identifier to the to-be-installed application set and/or delete (304, 404) an application software identifier from the to-be-installed application set, so that the server (110, 600, 800) obtains an updated to-be-installed application set. accessing (301, 401), by a device (200, 500, 700), a server (110, 600, 800), wherein the accessing (301, 401), by a device (200, 500, 700), a server (110, 600, 800) comprises: accessing, by the device (200, 500, 700), the server (110, 600, 800) by logging in to an associated account, wherein the associated account corresponds to a to-be-installed application set; after the accessing, by the device (200, 500, 700), the server (110, 600, 800) by logging in to an associated account: if third application software not belonging to the to-be-installed application set has been installed in the device (200, 500, 700), sending, by the device (200, 500, 700), an adding request for a third application software identifier to the server (110, 600, 800), wherein the third application software identifier indicates the third application software, so that the server (110, 600, 800) adds the third application software identifier to the to-be-installed application set based on the adding request; receiving (302, 402), by the device (200, 500, 700), an editing operation of a user for the to-be-installed application set in the server (110, 600, 800), wherein the to-be-installed application set comprises N application software identifiers, wherein N is a positive integer, the N application software identifiers are used to indicate corresponding to-be-installed application software, and the to-be-installed application software is application software backed up by another device in the server (110, 600, 800); and sending (303, 403), by the device (200, 500, 700), an editing instruction for the to-be-installed application set to the server (110, 600, 800) based on the editing operation, wherein the editing instruction is used to instruct the server (110, 600, 800) to add (304, 404) an application software identifier to the to-be-installed application set and/or delete (304, 404) an application software identifier from the to-be-installed application set, so that the server (110, 600, 800) obtains an updated to-be-installed application set.