According to the CBL feature extraction and denoising precise webpage classification method, feature extraction is performed on a data set, and noise data in the data set is removed. Firstly, feature extraction is performed based on a feature extraction method of a CBL model, original high-dimensional spatial features are mapped or converted into new low-dimensional spatial features, useless noise data is mapped to a weak dimension, feature items in an original space are greatly reduced, representative feature items are selected according to relevance of the feature items, and the purpose of dimension reduction is achieved. Secondly, noise data is removed based on a noise processing method of a CBL model, a data set is divided into a plurality of subsets according to categories to which the data set belongs, a probability feature topic model corresponding to each subset is constructed, information entropy values of webpages in the data set and the probability feature topic models of the subsets are calculated, and if the information entropy values of the webpages are larger than a given critical value, the webpage belongs to noise data, the junk information is cleared, and the accuracy and precision of webpage classification are greatly improved.