In the inter-working method of wireless Internet (gateways) according to the present invention described above, DIAMETER which is the first version of the IETF-RFC standard of mobile IP application is applied to the application scenario based on wireless Internet gateway of a home network, not on FA or HA of Mobile IP. After all mobile communication providers connect to wireless Internet, subscribers are not bounded to the network of their mobile communication provider and have the freedom to select any external wireless Internet portal site and use the service of it. Such a wireless Internet connection method will make wireless Internet contents popular in the open wireless network epoch and provide wireless Internet contents providers with an excellent chance. The authentication of the wireless Internet gateways of other networks, authorization, accounting management, structures and techniques proposed by the present invention can give solutions to security problems of wireless internet gateway (ex WAP G/W) that have not overcome, and provide reliability to wireless Internet electronic commercial trade service.