This paper presents a popular technology for the private communications, which is Wireless Local Area Network (WLAN). WLANs and wireless applications are growing up in many network environments. They are potentially useful and powerful, but due to their broadcast nature, the security of these systems is still far from the optimum. As to the technologies in WLAN have the basically secure flaws, so the WLAN security problems continues to be a major thorn in it's using. 802.11x may work eventually, but today it always requires the implementation of a proprietary authentication framework. In the paper, we present the basic techniques using in WLAN and analyze the security of it, at the end of the paper, there is a conclusion for WLAN security solving methods.