The embodiments of the present invention provide a secure establishment method, system and device of a wireless local area network. The method includes: acquiring, by a UE, a first key; the first key is a shared key of the UE and a network element equipment in a mobile communication network accessed by the UE when implementing air interface security, or is derived according to the shared key; deriving, by the UE, according to the first key and a derivation parameter to acquire a derivation key; establishing, by the UE, according to the derivation key, a secure connection with a WLAN node acquiring a derivation key, wherein the derivation key acquired by the WLAN node is the same as the derivation key acquired by the UE.