Objective To study the liver pathomorphological and serum biochemical changes in Beagle dog with spontaneous hepatocirrhosis and establish the backgroud information of experimental animals for GLP. Methods The ALT,AST,TP,ALB,ALP,TBIL,TC,TG and GGT were detected using an automatic biochemical analyzer,and compared the differences of above index between blank control and diseased animal.The histological changes of the liver were observed by optical microscopy. Results Compared with the blank control,the ALT,AST,ALP,TBIL and GGT of diseased dogs were increased significantly,and the ALB decreased significantly. Compared with normal dogs, the liver cells had nodular regeneration, arranged irregularly and pseudolobule formation.The pseudolobules were packaged with collagen fibers.Conclusion It is suggested that spontaneous lesions in Beagle dogs should be monitored so as to provide appropriate experimental animal histopathologicalbackgroud information for drug safety evaluation.