Aeromonas veroniiis widespread in aquatic environments and is capable of infecting various aquatic organisms.A. veroniiinfection is lethal for Chinese soft-shelled turtles (Trionyx sinensis, CSST). We isolated a gram-negative bacterium from the liver of diseased CSSTs, which was named XC-1908. This isolate was identified asA. veroniibased on its morphological and biochemical characteristics, and 16S rRNA gene sequence analysis.A. veroniiwas pathogenic for CSSTs with an LD50of 4.17 × 105CFU/g. The symptoms of CSSTs artificially infected with isolate XC-1908 were consistent with those of the naturally infected CSSTs. The levels of total protein, albumin, and white globule in the serum samples of the diseased turtles were decreased, whereas those of aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase were elevated. Moreover, the diseased CSSTs exhibited the following histopathological changes: the liver contained numerous melanomacrophage centers, renal glomerulus were edematous, intestinal villi were shed, and in oocytes, the number of vacuoles increased and red-rounded particles were observed. Antibiotic sensitivity tests revealed that the bacterium was sensitive to ceftriaxone, doxycycline, florfenicol, cefradine, and gentamicin, and resistant to sulfanilamide, carbenicillin, benzathine, clindamycin, erythromycin, and streptomycin. This study provides control strategies to prevent outbreaks ofA. veroniiinfection in CSSTs.