To explore the etiology of a serious infectious disease occurred in Rana grylio at a farm in Sichuan province, pathological examination and pathogen isolation were carried out for the diseased frogs. The isolated pathogen was identified by transmission electron microscopy, PCR detection and phylogenetic analysis. External clinical signs included swelling of limbs and ulcerations on body surface. The dead frog exhibited enlarged liver, spleen and kidney. Based on histopathological observation, we found that liver, spleen, kidney and other organs had damages with obvious degeneration and necrosis focus. The carp epithelioma papulosum cyprini ( EPC ) cell line inoculated with diseased samples under 25℃ and exhibited typical cytopathic effects ( CPE ) after four days exhibited typical cytopathic effects ( CPE ) ，such as rounding and shedding, with the TCID50 of 10-4.12/0.1 mL. Transmission electron microscopic observation showed that the virus was regular hexagon with capsule arrayed in crystallines, and the diagonal diameter was about 165 nm. PCR by using major capsid protein (MCP) gene specific primers was performed on the internal tissues of infected frogs and the EPC cells with CPE, and the results were positive. Phylogenetic analysis based on MCP gene sequences indicated that the sequences of isolated virus had over 99% identity to ranavirus, and belonged to FV3-like. The study confirmed that the isolated virus, named TSL210813, belonged to ranavirus, which was the cause of diseased R. grylio.