To investigate the effect and mechanism of pepsin-solubilized collagen peptides from of Lophius litulo skin (PSCP) on high fat diet (HFD) induced non-alcoholic fatty liver disease (NAFLD) in C57BL/6 mice. Forty-eight C57BL/6 mice were fed with high-fat diet for 4 weeks to induce the nonalcoholic fatty liver disease model. The mice were then treated with metformin, low, medium and high dose PSCP for 6 weeks. The serum physiological and biochemical indexes, liver oxidative stress level, liver histopathology changes and protein expression levels of the mice in each group were measured respectively. The experimental results show that compared with the model group, total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL-C), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in the positive drug group and high dose PSCP group were significantly decreased (P<0.05), and HDL-C levels were significantly increased (P<0.05). glutathione (GSH), superoxide Dismutase (SOD), and catalase (CAT) activities in liver of the positive drug group, middle dose and high dose PSCP groups were significantly increased (P<0.05), while malondialdehyde (MDA) contents were significantly decreased (P<0.05). Hematoxylin-eosin (HE) staining and transmission electron microscopy showed that the liver structure of the positive drug group and PSCP groups was significantly improved. The results of protein immunoblotting showed that, compared with the normal group, the protein expression levels of AMPKα, p-AMPKα, and IκBα in the liver of model group were significantly decreased (P<0.05), while the protein expression levels of SREBP-1, p65, p50, and IKKα were significantly increased (P<0.05). However, after administration of the positive drug and PSCP, the protein expression levels of AMPKα, p-AMPKα, and IκBα were increased, and the protein expression levels of SREBP-1, p65, p50, and IKKα were decreased. The result showed that PSCP could effectively improve the biochemical indices of NAFLD mice and restore the liver tissue structure, and the mechanism might be related to AMPK/NF-κB pathway transduction.