Social media becomes more important for the mainstream media. Based on content analysis and sentimental analysis, this paper tries to analyze how social media editors in mainstream media to operate posts. The results show that social medial editors like to use negative emotion words in the posts. The emotional words written by social media editors would not affect the readers on the Facebook. This research suggests mainstream media should carefully use emotional words in the posts and try to be more professional. The functions of social media editors could be meaningful for the audience.