A system differential upgrade method and apparatus, and a mobile terminal are provided. The method includes: obtaining an upgrade script and upgrade data; upgrading a file to be upgraded according to the upgrade script and the upgrade data; generating, according to the file processing command that is being executed currently in the upgrade script, and the file to be upgraded corresponding to the file processing command that is being executed currently, rollback data and a rollback script corresponding to the file to be upgraded; and when the upgrade fails, executing the rollback script according to the rollback data. The apparatus includes an obtaining module, an upgrading module, a generating module, and an executing module. According to the embodiments of the present invention, when an upgrade fails, the rollback script is executed according to the rollback data, which may restore a system to that before the upgrade.