In this research, bamboo-based nanocellulose was prepared and characterized using high-speed ball milling to reduce initial bamboo powder particle size for potential use in nanocomposites. FTIR analysis revealed structural modifications, including increased cellulose content and decreased lignin content post-treatment. XRD analysis indicated a shift from cellulose I to cellulose II, suggesting altered crystallinity and hydrogen-bonding networks. SEM analysis revealed distinct morphological changes between untreated and NaOH-treated bamboo fibers, with the latter exhibiting surface modifications indicative of effective treatment. Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM) images demonstrated a reduction in particle size to approximately 80 nm, with reduced aggregation and individualized nanofibrils. Tensile tests of bamboo nanoparticle-epoxy biocomposites with varying weight percentages (0.5%, 1%, 1.5%, and 2%) of nanoparticles showed enhanced tensile strength up to 1.5% loading (83.92±1.74 MPa), but a decrease at 2% loading (70.24±1.80 MPa), indicating increased strain-to-failure. SEM and TEM images illustrated a homogeneous distribution at 1.5 wt.%, but increased agglomeration at higher contents, impacting microstructure. This study underscores bamboo-derived nanocellulose's potential for tailored applications and improved mechanical properties in nanocomposites, highlighting the critical role of filler content in material performance and microstructure.