The invention discloses a method for mining the orientation of Web themes and supporting decisions. The method includes steps of S1, extracting and storing network information, acquiring information on the internet via a network mining technology, and storing results in a database and a local file system; S2, detecting and tracking viewpoint themes of the information, detecting and identifying interested viewpoint themes with complete semantic information by the aid of thematic comment data and keeping tracking and following the viewpoint themes; and S3, identifying the emotion orientation of the viewpoint themes, classifying the emotion orientation of hot topics of an enterprise, and mining the emotion orientation of the view themes. The method has the advantages that related business information is acquired from the internet, so that the tendency of the orientation of the themes related to the enterprise can be quickly and effectively mined from the massive network information, real-time business intelligence can be realized, and decision support service can be effectively provided for the enterprise.