Objective To observe the pathomorphological characteristics of acute bromadiolone poisoning in guinea pigs. Methods Isolate and identify pathogenic bacterial strain from the intoxicated guinea pigs, and dissect the animals for histopathological examination and toxicological analysis. Results No growth of pathogenic bacterial strain was observed in the blood in the heart, liver, mesenteric lymph nodes or small intestinal and cecal contents of the guinea pigs. The result of autopsy was well consistent with that of histopathological examination, The pathomorphological changes were revealed as extensive and extreme congestion in systemic tissues and organs, flecked bleeding in lung and heart muscle, flecked and diffuse bleeding in gastrointestinal tract, acute hemorrhagic and catarrhal gastrocnteritis, degeneration of parenchymatous organs such as heart, liver, kidney and adrenal, and diffuse pulmonary emphysema, Bromadiulone was detected in the intoxicated guinea pigs. Conclusion The pathological changes of guinea pigs, which were orally administered with bromadiolone, are characteristic of anticoagulant poisoning, The study provided a reliable basis for rapid diagnosis and treatment of bromadiolone poisoning.