Barrage derives from a second creation of video text under the Internet technical support. Taking barrage video as its field, barrage constructs a carnival for audiences of barrage video. Methods of participant observation and content analysis are used. Combining its informed researches with its state quo, this paper gives a redefinition of barrage. Based on the theory of carnival put forward by Bakhtin, construction mechanism and effects of the carnival constructed by barrage in barrage video are analyzed and evaluated. Regarding the theory of carnival as the frame, this paper aims to do analysis of barrage's use value such as satisfying of audiences' seeking on free and equal participant or on self-identified and to probe deeply into the possible result that amuses to death leaded by barrage and limitation of barrage users' characteristics of small mass.