Biomass materials are high-quality raw materials for the preparation of natural, green and highly active functional materials due to their rich active groups, wide sources and low toxicity. Bagasse xylan (BX) and resveratrol (Res) were used as raw materials to introduce ethylene glycol dimethacrylate (EGDMA) via grafting reaction to obtain the intermediate product BX/Res-g-EGDMA. The intermediate was esterified with 3-carboxyphenylboronic acid (3-CBA) to obtain the target product 3-CBA-BX/Res-g-EGDMA. The BX/Res-composite-modified nanoderivative with antitumor activity was synthesized with the nanoprecipitation method. The effects of the reaction conditions on the grafting rate () of BX/Res-g-EGDMA and the degree of substitution () of 3-CBA-BX/Res-g-EGDMA were investigated using single-factor experiments. The results showed that under the optimized process conditions, and reached 142.44% and 0.485, respectively. The product was characterized with FTIR, XRD, TG-FTC, H NMR and SEM, and its anticancer activity was simulated and tested. The results showed that 3-CBA-BX/Res-g-EGDMA had a spherical structure with an average particle size of about 100 nm and that its crystalline structure and thermal stability were different from those of the raw materials. In addition, 3-CBA-BX/Res-g-EGDMA showed the best docking activity with 2HE7 with a binding free energy of -6.3 kJ/mol. The inhibition rate of 3-CBA-BX/Res-g-EGDMA on MGC80-3 (gastric cancer cells) reached 36.71 ± 4.93%, which was 18 times higher than that of BX. Therefore, this material could be a potential candidate for biomedical applications.