Abstract: The bag of word model is first improved according to the social media short text feature. The semantic representation model is then proposed by using semantic relations between features. The sequence diagram model can be constructed by using the sequence of features in the sentence. On the base of these, together with time factor, we propose a user interest topic mode based on Single-Pass to extract the topic of user's attention. The experimental results show that the FM, AA and F of our method are increased by 200.40%, 46.50% and 80.05%, respectively, compared with the latest method FSC-LDA.