Online reviews and comments are important information resources for people.A new model,called Sentiment Vector Space Model (SVSM),for feature selection and weighting is proposed to predict the sentiment orientation of comments and reviews,e.g.,sorting out positive reviews from negative ones.Different from that of topic-oriented classification,feature selection of sentiment orientation prediction focuses on language characteristics.Different from traditional algorithms for sentiment classification,this model integrates grammatical knowledge and takes topic correlations into account.Features are extracted,and the similarity between these features and the topic are also computed.The feature similarity is taken as a factor when evaluating the polarity of opinions.The experimental results show that the proposed model is more effective in identifying sentinment orientation than most of the traditional techniques.