This application provides a patch package generation method and a device, which includes: when code of an application framework layer in Android operating system source code is updated, obtaining, by a server, a compilation result; determining, by the server, an Android package (APK) of a target application from the APK of the preinstalled applications by, determining, by the server, an application including code in which only one or more of a check value, a timestamp, and a register corresponding to a constant change; and differentiating, by the server, an APK of an application other than the target application in the preinstalled applications after the code of the application framework layer is updated and an APK of the application other than the target application in the preinstalled applications before the code of the application framework layer is updated, to generate a first differential package. The first differential package is relatively small, therefore reducing computation amount in the terminal and air interface consumption.