Abstract: Bullet screen video is a kind of real-time interactivity in which bullet is the main online communicative means. This form of interaction has the characteristics of multimodality and multithreading, including two interactive spaces, “man-machine” and “interpersonal”. These two spaces are connected by conversion of conversation roles. Different from offline conversation, this interaction constructs a synchronic psychological time system with the “my view” as a reference. The discourse sequence is mainly parallel and sequential, and is often dynamic. This new form of interaction is not only meeting the inevitable need of communication in the new media era, but also the result of shaping and restricting communication interaction by the media.