Abstract: Rotten-skin disease is very common in the artificial culture of the giant spiny frog (Quasipaa spinosa). To screen pathogenic bacteria that cause illness of giant spiny frog, gram stain, morphological observation, physiological, and biochemical identification, and sequence analysis of 16S rDNA were performed and three bacteria (BS₁, BS₂, and BS₃) were identified. The results showed that BS₁, BS₂, and BS₃ are Bacillus cereus. Liver, lung, tongue, and muscle were impaired with degeneration, necrosis, and inflammatory cell infiltration. Moreover, basophilic inclusions were observed in the lung of diseased giant spiny frog. The drug sensitivity test showed that all three pathogenic bacteria were highly sensitive to gentamicin and streptomycin, moderate sensitive to tobramycin, kanamycin and tetracycline, and resistant to ampicillin and ceftazidime. This study explored pathogenesis of rotten-skin disease of giant spiny frog, would provide theoretical basis for prevention and cure of rotten-skin disease of giant spiny frog.