Abstract: Grouper ranavirus infected many grouper species and caused severe mortality. We isolated a grouper iridovirus (genus Ranavirus) 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 observed 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.