A type of oligosaccharide named mulberry galacto-oligosaccharides (MGO), was isolated from mulberry with a galactose-only, weighs 987 Da and displays diverse biological properties. The objective of this work was to investigate the protective effects of MGO in non-alcoholic fatty liver disease (NAFLD) mice. The results showed that MGO can reduce the body weight and liver weight of NAFLD mice, and reduce the levels of NEFA, TG, TC and LDL-C in serum and liver as well as the activities of AST and ALT. Increase HDL-C content, SOD, and GSH activity in serum and improve pathological damage. MGO regulates the AMPK lipid metabolism pathway, upregulates the expression of ATGL, downregulates the expression of SREBP-1, inhibits lipogenesis, and promotes lipolysis. MGO alleviates liver function damage in NAFLD mice, improves blood lipids, liver metabolism, and increases the body’s antioxidant capacity, suggesting MGO potential as a dietary supplement and functional food to combat HFD-induced NAFLD.