AbstractIn order to improve the erosive wear resistance of bamboo fiber‐reinforced high‐density polyethylene (HDPE) composites, the effect of aluminum oxide (Al2O3) on the erosive wear behavior of composites was investigated. The study of erosive wear was using the swirling water jet technique. The results showed that the addition of nanoscale Al2O3 could optimize the structural strength, composite structure, and erosive wear resistance of composites. The best erosive wear resistance was observed in composites containing 6/189 wt% of nanoscale Al2O3, 80/189 wt% of bamboo fiber, 100/189 wt% of HDPE, and 3/189 wt% of maleic anhydride grafted polyethylene. The composites with and without adding nanoscale Al2O3, both exhibited a maximum erosive wear rate at a shooting distance of 0.5 cm and an erosive duration of 180 s. The erosive wear mechanism of composites mainly included pulverization of bamboo fibers, brittle fracture of HDPE matrix, and increasing in oxygen content.