In the case of the lack of large-scale opinion-sentiment corpus in the hospital comment area, the paper expounds on the current study situation of the sharing of domestic and overseas medical community knowledge and the opinion mining and sentiment analysis based on characteristics. Using the characteristic rule method, it implements opinion mining and sentiment analysis of the comments on seeking medical advice in hospitals made by users of online medical community on the basis of supplementing the sentiment lexicon and carries out empirical analysis. Results show that mining effect of the method is good.