The invention discloses a method and a device for updating application programs. The method comprises the following steps of: acquiring one or more first files of a first version of the application programs, and one or more second files of a second version of the application programs; generating the update difference files of the one or more first files and the corresponding one or more second files; issuing the update difference files comprising download addresses; generating configuration files comprising the version information of the second version and the download addresses of the update difference files; issuing the configuration files. According to the method and the device disclosed by the invention, clients are prevented from blindly accessing a server to request to update service, thus reducing the response frequency of the server and decreasing the resource consumption of the server; meanwhile, the volume of each of the update difference files produced by data difference is greatly reduced compared with a complete version update data package, thus greatly reducing network bandwidth resources, and increasing download success rate and update success rate.