This study aims to develop a strategy to promote the mechanical properties of nanofiller/polymer composite nanofibers, i.e., nanofillers was modified with hyperbranched polyglycerol (PG) by ring-opening polymerization of glycidol. The accomplishment of grafting of PG on ND nanofiller surface was confirmed by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and thermo gravimetric analysis (TGA). FITR and differential scanning calorimetry (DSC) results revealed the enhanced filler-PVA interactions following PG functionalization. The improved dispersivity of PG-functionalized NDs (ND-PGs) in water and PVA matrix was verified by sedimentation tests and TEM, respectively. The grafting of PG on ND surface increased the tensile strength up to 60 %, Young's modulus up to 51 %, and toughness up to 59 %, for 3 wt% ND/PVA composite nanofiber membranes. Therefore, the enhanced mechanical performance of ND-PG/PVA nanocomposites can be attributed to the enriched hydroxyl groups of PG which improved the dispersion of nanofillers within composite matrix and strengthened filler-matrix interactions.