Abstract: We cloned three grass carp (Ctenopharyngodon idellus) gcjam-a genes (gcjam-a1, gcjam-a2 and gcjam-a3) and used qRT-PCR to analyze their expression pattern in nine tissues of grass carp, as well as their expression after grass carp reovirus-GD108 strain infection. The three gcjam-a genes had 294~295 amino acids and two immunoglobulin Ig domains, including typical receptor binding domain D1 and transmembrane domain D2. The D2 domains of gcjam-a genes were identical while D1 domains were slightly different. In nine tissues of healthy grass carps, gcjam-a1 was mainly expressed in blood and brain, and gcjam-a2 was mainly expressed in the gills, but gcjam-a3 could not be detected in all tested tissues. After the virus infection, gcjam-a1, gcjam-a2 and gcjam-a3 increased in gills significantly; only gcjam-a1 increased in liver, spleen, intestine, kidney and brain. The gcjam-a1, expressed highest in healthy grass carps tissues among the three gcjam-a genes, increased in all six tissues after the virus infection, which suggests that it might be the main receptor of GCRV-GD108.