Microblog is a relation-based platform for sharing, spreading and acquiring information, and also the source of internet public opinion and the important battlefield of information transmission. The convenient forwarding operations of microblog result in the rapid spread of plenty of identical or similar microblog pages in the microblog space. Therefore, the detection of similar microblog pages is of great importance to lighten the client’s burden of browsing and improve the analytic efficiency of internet public opinion. A method based on LCS is introduced to detect similar microblog page: First is to calculate the files’ subset of the possibly similar microblog pages, and the next is to calculate its LCS and extract the reliable parts so as to ultimately detect the similar microblog pages. Experiments show that this method can detect the similar pages from the microblog data accurately and efficiently.