In the environment of information and networking, learners' learning should not be limited in a specific time (school hours) or a specific space(the classroom), or even because of time and space to influence the students' learning. Microblog is an application form of new technology based on web2.0. This study analyzes the characters and structures of microblog system. Using the educational practice of microblog system as a starting point, we discuss the application mode of educational microblog system in informal learning community.