The invention provides a method of improving a wireless local area authentication mechanism. After a wireless access point sends a message that the authentication is successful in a plain text to a client in a bidirectional authentication process, the method comprises the steps of providing a first encryption parameter, if the first encryption parameter remains unchanged after being encrypted by the client, decrypted by the wireless access point, encrypted by the wireless access point and decrypted by the client, judging that the wireless access point is legal; providing a second encryption parameter, if the second encryption parameter remains unchanged after being encrypted by the wireless access point, decrypted by the client, re-encrypted by the client and re-decrypted by the wireless access point, judging that the entire authentication process is completed. The method of improving the wireless local area authentication mechanism provided by the invention can effectively prevent the "man-in-the-middle attack", i.e., the illegal user is unable to access the network through the port of the legal user, so as to avoid the "communication hijack" attack.