Feature extraction is one of the key steps in text sentiment analysis,which is also the main factor that affects the result.According to the variant expression of online review,the synonyms TF-IDF(term frequency-inverse document frequency) weight vector is obtained based on the semantic similarity. Then in viewof the different length of online review,the local patterns of the feature vectors are identified with OPSM(order-preserving submatrix) biclustering algorithm. We improve Prefix Span algorithm to dete...