Objective To explore the effect of diosmetin on non-alcoholic fatty liver disease of young rats induced by high-fat diet. Methods The rats models of non-alcoholic fatty liver disease were induced by high-fat diet. The levels of serum lipid and inflammatory factors were detected by enzyme-linked immunosorbent assay (ELISA). The pathological changes and apoptosis of liver tissues were observed by hematoxylin- eosin (HE) staining and terminal deoxynucleotidyl transferase- mediated dUTP nick labeling (TUNEL). The levels of p-AMPKα1, AMPKα1, CPT-1, PPAR-α, SREBP-1c, FAS, p-P38, P38, p-AKT, AKT, p-AKT, AKT were tested by western blot. Results Compared with control group, the levels of TC, TG, LDL-c in high fat diet group were increased with declined levels of HDL-c (P<0.01). Compared with high fat diet group, the levels of TC, TG, LDL-c in diosmetin (10, 20, 50 mg/kg) groups were reduced with enhanced levels of HDL-c (P<0.01). The high fat diet-induced pathological changes of liver tissues were reliefed by diosmetin. The apoptosis of liver tissues in high fat diet group was higher than that of control group (P<0.01). The apoptosis of liver tissues in diosmetin (10, 20, 50 mg/kg) groups was lower than that of high fat diet group (P<0.01). The levels of p-AMPKα1, CPT-1 and PPAR-α in high fat diet group were lower than that of control group (P<0.01). Compared with high fat diet group, the levels of p-AMPKα1, CPT-1 and PPAR-α in diosmetin (20, 50 mg/kg) groups were elevated (P<0.01). The levels of SREBP-1c and FAS in high fat diet group were higher than that of control group (P<0.01). Compared with high fat diet group, the levels of SREBP-1c and FAS in diosmetin (10, 20, 50 mg/kg) groups were decreased (P<0.01). Moreover, the levels of IL-6, IL-1β and TNF-α in high fat diet group were higher than that of control group (P<0.01). Compared with high fat diet group, the levels of IL-6, IL-1β and TNF-α in diosmetin (20, 50 mg/kg) groups were reduced (P<0.01). In addition, the inhibitory effect of compound C on AMPK pathway was reversed by diosmetin. Conclusion Diosmetin alleviates the abnormal lipid metabolism, pathological changes of liver tissues, apoptosis and inflammatory response in high-fat diet-induced non-alcoholic fatty liver disease rats by activating AMPK pathway.