The invention discloses a method, a system, a wireless sharing device and a terminal for accessing a wireless local area network. The method mainly comprises the steps that the wireless sharing device broadcasts an external identifier and an internal identifier to terminals; the terminal selects an identifier to be carried in an access request message from the identifiers received, so that when the wireless sharing device determines that the access request message carries the external identifier, the terminal is authenticated through an external authentication server; when the wireless sharing device determines that the access request message carries the internal identifier, the terminal is authenticated by means of registering information stored locally; regardless of the external or internal authentication process, if authentication passes, the terminal is permitted to be accessed to the wireless local area network; otherwise, the terminal is rejected to be accessed to the wireless local area network. Thus, terminals supporting internal and external authentication modes can be accessed to the wireless local area network. Under the premise of ensuring the safety of the wireless local area network, the utilization rate of the wireless local area network sources is improved.