Abstract: There are two methods that can be used to determine the interesting topic in designing a focused crawler：setting keywords manually or constructing a classifier.Although the former can be easily implemented，it depends on the expert’s experience and has disadvantages about leaks of keywords and imprecise quantification of the keyword’s weight.The major defect of the later is that it is difficult to acquire typical negative training examples.To solve these problems，a focused crawler based on one-class document classification is proposed.The classification can act on not only the content of the web document，but also the hyperlink’s anchor text.The result of the experiments shows that the proposed focused crawler is feasible.