The invention discloses a security evaluation method and device for a wireless local area network, and belongs to the technical field of Internet. The method comprises the following steps: receiving an operation request sent by a client through accessing the wireless local area network, and acquiring identifier information of the wireless local area network and an identifier of the client carriedin the operation request; acquiring multiple behavior information of multiple clients connected with the same wireless local area network; generating behavior data of the wireless local area network according to the behavior information of the multiple clients; enabling the behavior data to be associated with a network malicious behavior; and evaluating the security of the wireless local area network according to the behavior data of the wireless local area network. According to the security evaluation method for the wireless local area network provided by the invention, data of the associatedclients of the wireless local area network can be actively collected, and the security of the wireless local area network is evaluated by analyzing the data; and a user is notified in time when the user is connected to the wireless local area network, particularly a malicious wireless local area network, so that the privacy and safety of the user are protected.