Abstract: To explore the protective effects of water extracts from different Ganoderma lucidum (G. lucidum) mycelium on ethanol-induced hepatocyte injury in LO2 cells. The effects of water extracts obtained from different G. lucidum mycelium against ethanol-induced damage to LO2 cells were examined in this research. Cell survival rate, alanine aminotransferase (ALT), aspartate aminotransferase (AST), reactive oxygen species (ROS), superoxide dismutase (SOD), glutathione (GSH) and malondialdehyde (MDA) levels were measured in a liver injury model employing ethanol-induced LO2 cells, to assess the preventive effects of G. lucidum mycelium water extracts against ethanol-induced damage. The results showed that water extracts from the mycelium of all seven strains exhibited varying degrees of protective effects. Among them, the water extract from strains G0119 and G0154 had the best protective effect. Compared with the model group, the intervention of water extracts significantly increased LO2 cell survival (P<0.05), while decreased ALT and AST levels in the cell culture medium, respectively (P<0.05). Furthermore, the intracellular ROS level significantly decreased, while the activity of SOD and the content of GSH significantly increased, and the MDA content significantly decreased compared to the model group (P<0.05). Correlation analysis revealed a positive correlation between the molecular weight of polysaccharide component 2 in the water extract and its hepatoprotective activity, with higher molecular weight correlating with stronger activity. The results indicated that the water extract of G. lucidum mycelium exhibited a protective effect against ethanol-induced in vitro liver damage. Moreover, the effectiveness of the G0119 and G0154 strains were superior, and its hepatoprotective effect was correlated with the molecular weight of polysaccharide components in the extract.