Abstract: A roaming network registration method executed via a wireless communication device is provided. The method comprises the following steps: executing a search in a latest registered supported network type of a plurality of supported network types based on a first database; obtaining a first mobile country code transmitted via at least one public land mobile network when the public land mobile network is searched; comparing the first mobile country code with a second mobile country code corresponding to a latest registered public land mobile network of the wireless communication device; and determining that the wireless communication device is in a roaming state when the first mobile country code is different from second mobile country code.