In recent years, advancement of science technology and ubiquitous use of networking have led to a great increase of the need for high speed wireless internet. This has encouraged the existing Wireless Local Area Network(WLAN) system to build a new territory in the information and communication market. It provides with reasonable price and convenience, however, its connectivity, transmission speed and mobility do not meed consumers' expectations. In this paper, the standards for grading quality according to the purposes of the WLAN service, applying the concept of composition cause of the service quality that has already been agreed upon, will be reconstructed. Also, this study will try to measure the achievements of the actual WLAN service quality by utilizing the realized measurement standards.