In the field of communications, a method, a system, and devices for implementing a network banking service are provided. The method includes: after an agent device establishes a connection with a Point Of Sale (POS) device, the agent device performs identification with the POS device; after successful identification, the agent device performs authentication with the POS device; after successful authentication, the agent device establishes a connection with a network banking server according to a preset address of the network banking server through wireless access to the Internet; and the agent device forwards network banking service data between the POS device and the network banking server, thereby implementing the network banking service. Therefore, it is convenient for users to use a network banking service, the functions of POS devices are simplified, and the cost of manufacturing and maintaining POS devices is reduced.