Abstract: This study investigated the effects of sulfadiazine exposure at three different concentrations (1 μg/L, 100 μg/L and 10 mg/L) for 28d on histopathology of the liver, kidney, gill, muscle and gut of Carassius auratus gibelio by semi-static test method. The results showed that different pathological changes occurred on the liver, kidney, gill and muscle of Carassius auratus gibelio under different concentrations of sulfadiazine stress, which included the congestion, vacuolation, karyopyknosis, necrosis of liver cell, the vacuolar degeneration of epithelial cells, necrocytosis in glomerulus and congestion in renal interstitium, the edema of epithelial cell in gill lamellae, hyperplasia and disappearance of gill lamellae, the exfoliation of microvilli, thicker submucosa and vacuoles degeneration and necrosis of muscularis, the widened gap, disorder and fragmentation of myofiber. Among all the tissues, liver, gill and kidney presented more serious pathological lesions than other two tissues and damage of tissues was inhibited obviously in a time and dose dependant manner. Thus, this study can provide theoretical guidance for the rational use of sulfonamides drugs in the aquaculture process.