The purpose of this study was to investigate the anti-injury effect and protective mechanism of hydrogen-enriched water in a rat model of acute liver injury induced by aflatoxin B1 (AFB1). Healthy male Sprague-Dawley (SD) rats were randomly divided into control group, model group (AFB1 group) and hydrogen-enriched water treatment group (AFB1+H2 group). The rat model of acute liver injury induced by AFB1 was established by single intragastric administration of AFB1 (2.0 mg/kg), and then the rats were treated with hydrogen-enriched water intragastrically. HE staining was used to observe the pathological changes of liver tissue. Blood samples were taken from vena cava to measure serum liver function indexes. Live tissue was sampled to detect malondialdehyde (MDA) and reduced glutathione (GSH) contents. Western blot was used to detect phosphorylation levels of MAPK signaling pathway proteins (ERK, JNK and p38 MAPK). The results showed that, compared with the AFB1 group, the AFB1+H2 group exhibited increased body weights, alleviated acute liver injury, decreased activities of serum glutamic-pyruvic transaminase and glutamic oxaloacetic transaminase, as well as total bilirubin level in the serum. Meanwhile, hydrogen-enriched water decreased MDA content and increased GSH content in liver tissue. AFB1-increased phosphorylation levels of ERK, JNK and p38 MAPK in liver tissue were down-regulated significantly by hydrogen-enriched water treatment. These results suggest that hydrogen-enriched water can alleviate liver injury induced by AFB1, and its mechanism may be related to the reduction of oxidative stress and the inhibition of MAPK signal transduction pathway activation.