The invention relates to the network communication field, particularly an access method, an access device and an access system. The method comprises the following steps: receiving a message of a first single board; conducting loopback processing for the message; conducting related business processing for the message; and forwarding the message to a network side or a user side through a route. Thefirst single board is connected with a physical link of an access network; and the message enters the access network terminal processing. Through the technical scheme provided by the embodiment of the invention, the problem that the business specification is influenced by the single board is solved for a wire can be laid on the single board which is not directly connected with physical link.