The personification of government microblogs means that government microblogs are endowed with virtual personality. This strategy can make a government microblog interact with the Internet users with the identity of a virtual natural person. Personification is widely used in government microblogging, but there is a problem of over personification, such as “flip interaction” and “negative interaction”. Within the frame of theories about social cues, the controlled experiment of 2×2×2 factorial design including three independent variables of biography, expressive style and content and three dependent variables of the effects on its image construction, information transmission and relationship with the public reveals the effect called “the cover effect”. Based on that, the specifc points are suggested to optimize the personifcation of government microblogs.