Abstract: In order to achieve the goal of antibacterial functional modification of polyester fabrics, the homemade amino-terminated hyperbranched polymer was applied as a reducing agent to produce nano silver. A suitable finishing process was proposed to treat polyester fabrics with nano silver solutions. The fiber surface of the treated polyester was observed by SEM. The antibacterial efficacy, whiteness and washing durability of the treated fabrics were determined. The results showed that the average diameter of nano silver was within 20nm and its stability was excellent. The treated polyester fabrics had 99.42% bacterial inhibition ratio against Staphylococcus aureus and 99.27% bacterial inhibition ratio against Escherichia coli, while the silver content on polyester was 125.412mg/kg. The treated fabrics had 98.32% bacterial inhibition ratio even after 50 washing cycles. The washing durability of the treated fabrics was good.