Objective:To investigate the protective effect of Liuwei Dihuang pill on liver injury in mice with yin deficiency induced by thyroxine. MethodsThirty ICR mice were randomly divided into normal group, model group and Liuwei Dihuang pill group (1.8 g crude drug/kg). Except for the normal group, mice in the other groups were injected subcutaneously with L-thyroxine (280 μg/kg) solution to establish the model of yin deficiency. One week later, the solution of Liuwei Dihuang pill was given by intragastric administration, while L-thyroxine was continued to be administered subcutaneously for 3 weeks. During this period, body mass, temperature, number of locomotor activities, pain threshold and heart rate of the mice were measured to evaluate the yin deficiency model and antagonistic effect of the drug. At the end of experiment, the serum activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and contents of total protein (TP), total cholesterol (TC) and triglyceride (TG) were determined; the liver was dissected and weighed to calculate the liver index; the contents of phosphocreatin (PCr), adenosine triphosphate (ATP), adenosine monophosphate (ADP), adenosine monophosphate (AMP) and cyclic adenosine monophosphate (cAMP) in liver were determined by HPLC and the total adenylate content TAN (ATP+ADP+AMP) was calculated.  Results:The yin deficiency indicators such as body mass, temperature, number of locomotor activities, pain threshold and heart rate of the model mice were abnormal, and Liuwei Dihuang pill showed certain effect in improving these Compared with the normal group, the liver index and the serum activities of ALT and AST increased significantly, the serum levels of TC and TP decreased significantly and the contents of ATP, ADP, AMP, cAMP and TAN in liver tissues decreased significantly in the model group(P<0.05,P<0.01). Compared with the model group, the serum activities of ALT and AST decreased significantly in the Liuwei Dihuang pill group, the serum levels of TC and TP increased significantly, and in liver tissues, the contents of ADP, cAMP and TAN increased significantly(P<0.05,P<0.01), and the contents of ATP and AMP also increased in the Liuwei Dihuang pill group.  Conclusion:Liuwei Dihuang pill has a certain protective effect on liver injury induced by L-thyroxine in mice with yin deficiency, which may be related to the improvement of energy metabolism disorder in liver tissues.