Abstract: A novel method for Email filtering is proposed based on the information of character fields and the frequency of the terms in the character fields. The techniques used in the method are discussed, which include selecting the characters of text documents, the constructing the character lexicons as well as the computation of the weights of the term frequency (TF). In addition, an improved probabilistic model for the computation of the similarity of among text documents is provided. Experiments show that the new method is better than traditional Rocchio method in terms of recall, precision and some other evaluation targets.

Key words: weight calculation , term frequency, character term lexicon, character field, spam filtering