Based on analysts' microblogs,this paper examines whether social media improve the efficiency of information dissemination of analysts. Our results show that,compared with analysts without microblogs,microblog-analysts can disseminate information more efficiently after opening microblogs. Once analysts stop issuing new blogs,this effect disappears. In addition,the more attention the analysts' microblogs attract,the higher information dissemination efficiency. Further analyses show that,the above effects only exist for star analysts and companies with higher institutional ownership,implying that star analysts and institutional investors are the main components of information supply and demand sides. Our paper provides evidence for studying the role of analysts' social media in capital markets.