Efficient water-based energy harvesting is gaining attention due to its potential for sustainable electricity generation. Among various hydrovoltaic technologies, evaporation-induced electricity generation is particularly promising, as it utilizes spontaneous water evaporation without requiring external stimuli. Wood, with its hierarchical porous structure and water transport properties, has emerged as a potential material for hydrovoltaic applications. However, the performance is generally low mainly due to inferior nanostructure control, E.g. low surface charge density, specific surface area and limited nanoporosity. Delignification has been intensively applied for wood treatment, resulting in enhanced charge density and improved nanoporosity. Therefore, in this study, we investigate the impact of delignification on the hydrovoltaic behavior of wood. The materials are characterized in detail. The results show that delignification enhances porosity, nanopore density, and hydrophilicity, leading to an increase in open-circuit voltage output but a decrease in short-circuit current. These findings suggest that delignification should be optimized for enhanced energy harvesting using wood-based hydrovoltaic generators.