World Wide Web(WWW) services have grown to levels where significant delays are expected to happen.Technology like prefetching are likely to help users to personalize their needs ,reducing their waiting times. This paperfirstly describes the architecture of prefetching,then classifies them into three types: based on branch model,based ontree model and others and presents profoundly the basic ideas of some existing prefetching algorithms. Next,severalmodels for controlling the prefetching are introduced. At last ,the trend and course concerning the prefetching algo-rithms are concluded.
