Grouper ranavirus infected many grouper species and caused severe mortality. We isolated a grouper iridovirus( genus Ranaυirus)named GIV-R-SY1301 in Sanya by using cell culture,to study the tissue distribution of GIV-R-SY1301 in experimentally infected farmed Epinephelus lanceolatus by in situ hybridization and real-time PCR. The GIV-R-SY1301 was widespread in all tissues from infected fish. Strong hybridization signals were obtained from kidney and spleen,while intermediate intensity signals were ob-served in stomach,gill and liver. The weakest signals were obtained from heart and no signal was found in brain and eye. The real-time PCR results show that there were most viruses copies in spleen,kidney and heart(4. 5 × 104 ~ 6. 85 × 107 copies·μg-1 )DNA in different tissues,which was similar with the result of in situ hybridization.