The invention provides an approximate web document detection method based on content and position features. In the approximate web document detection method disclosed by the invention, noise information in a page is eliminated before webpage features are calculated; therefore, influence of the noise content in the page on an approximate web document detection process can be effectively reduced; on the basis of selective analysis of a page text, in combination with a key concept, distribution characteristics and position features in a webpage text are compared, such that the approximate page detection precision is increased; the advantages of an indexing mechanism and a retrieval system in massive data are sufficiently utilized; a reverse index is used as a storage and access medium for keyword item vectors and position feature vectors in the page; the execution efficiency and the feasibility of the method are improved; in the method disclosed by the invention, the page content and the position feature vectors are used as basis for approximate page judgement; dependence on a related corpus and a conception semantic net is greatly reduced; the applicability of the method is enhanced; and thus, the approximate detection range of web documents is widened.