The invention relates to a method and device for safe access to a wireless local area network (WLAN). The method comprises the following steps: receiving pre-registration of valid APs in the wireless network to establish a secure database; dynamically recording association information between STAs and the valid APs currently reported by the valid APs to establish a dynamic database; scanning surrounding wireless signals through a valid discoverer AP, and capturing data messages exchanged between a scanned STA and a scanned AP; with an MAC address of the scanned AP serving as a keyword, searching the secure database for an identical MAC address; if the identical MAC address is found out, with the MAC address of the scanned AP, an MAC address of the scanned STA, and an association relationship between the scanned AP and the scanned STA serving as keywords, searching the dynamic database for an identical association relationship; and if the identical association relationship is not found out, determining that the scanned AP is an invalid AP. Through the method and device provided by the embodiment of the invention, user losses caused by access of the STA in the wireless network to the invalid AP are prevented, and the wireless network access security is improved.