Gut microbiota are integral components of the host, and received increasing attention. However, for many aquaculture animals, information on the intestinal microbiota is insufficient and more effort should be exerted to manage the intestinal microbiota for nutrition, immunity and disease control. In this study, changes of the intestinal microorganism of gibel carp (Carassius auratus gibelio) associated with cyprinid herpesvirus 2 (CyHV-2) infection were estimated by 16S rRNA gene amplicon sequencing. Results showed that: the diversity indices of intestinal microbiota were strongly reduced and the composition was also dramatically shifted afterCyHV-2 infection. The most dominant species in the healthy fish were Cetobacterium, Rhodobacter, and Crenothrix. While Cetobacterium, Plesiomonas, Bacteroides, and Flavobacterium were the most abundant species in the sick fish, and due to the high abundant of Plesiomonas, it could be choosen as a potential microbial biomarker forCyHV-2 infection. To conclude, the intestinal microbiota were highly affected byCyHV-2 infection and might play important roles in the development of disease infection.