Although windmill palm fiber is an abundant cellulose resource, it has not been efficiently used owing to the lackof the basic knowledge of its structure and properties. In this study, the surface morphology of windmill palm fiber wasmodified using acetyl chloride and acetic anhydride to generate hydrophobic nonwoven mats with optimal acousticproperties. A scanning electron microscope, a specific surface porosimeter, an infrared spectrum, and a standing wave tubewere used to examine the fiber’s micromorphology, pore structure, chemical composition, and sound absorptionperformance. Acetylation treatment damages the compact structure of the cell wall, resulting in the formation of nanoscalepores. Acetyl chloride changes the average pore diameter of fibers by 17 nm. When the polyvinyl alcohol content was 0.5 %and the surface density of mat was 0.140 g/cm2, the sound absorption coefficient for the acetic anhydride-modified fiber was0.66, which is 65 % greater than that of the untreated windmill palm fiber nonwoven mat. The windmill palm fiber has goodpotential for application in wallpaper and filling materials used at home.