The present invention provides a security system and method for a remote device in a wireless wide area network which particularly provides a remote use authority according to a system unique code and a network identification code. The present invention is characterized in that, when the remote processing device is connected to a network server, a network connecting module and a basic input output module of a remote processing device produce the network identification code and the system unique code, which the network server receives, and after verifying the network identification code and the system unique code, then a use authority is produced and transmitted back to a control module of the remote processing device, thereby controlling authority management when the operating system within a storage module is executing application programs.