With the rapid development of Internet ,Web usage mining plays very important role in many fields includ-ing personalizing information service ,improving designs and service of Web sites ,developing the personal electric com-merce ,building adaptive Web sites, promoting the reputation and income of Web sites. The paper introduces the defi-nition and classification of Web mining firstly,then the main technology and method of Web log preprocessing,the pri-mary algorithm of Web usage mining ,the evaluation method and important applications of Web usage mining are dis-cussed in detail. At the end ,the trend and research course concerning the Web usage mining are concluded.
