AbstractBall-milled bamboo was pre-swelled with a cold aqueous solution of NaOH and urea, and then reacted directly with benzyl chloride to synthesize benzylated bamboo. The effects of the molar ratio of benzyl chloride to OH groups in the bamboo (1 to 4), the reaction temperature (70 to 110 °C), and the reaction time (2 to 8 h) on both the product yield and the degree of substitution (DS) were evaluated. Yields between 67.6 and 94.0% and DS between 0.31 and 0.74 of the benzylated bamboo were obtained under such conditions. The incorporation of benzyl groups was evidenced by FT-IR and CP/MAS 13C-NMR spectroscopy. It was found that the crystalline structure of the native ball-milled bamboo was markedly damaged after modification. In addition, the benzylated bamboo was subjected to thermal degradation at a high temperature with an increase in substitution. It was suggested that the benzylated bamboo with a low crystallinity as well as large non-polar groups is promising as a filler for use in the composite material industry.