Abstract: Suspected cases of pregnancy toxaemia of Small-tail Han Sheep in a scaled sheep farm in south Xinjiang were diagnosed and analysis by epidemiological investigation, clinical diagnosis method, pathological observation and laboratory examination. The histopathologic changes of the diseased sheep were as followed： the liver enlarged and its section was valgus and greasy, the myocardial cells degenerated and the heart became brittle, the bleeding points were observed in endocardium and epicardium, indicating the typical clinical symptoms of pregnancy toxaemia. The serum content of ALT, AST, ALP and ALB of the diseased sheep was significantly higher than those of the healthy sheep in the same farm（P〈0.05）, and was also obviously higher than the normal reference range of the healthy sheep. The combined diagnosis results demonstrated that the emerged disease in Small-tail Han Sheep in the sheep farm was pregnancy toxaemia.