The homemade amino-terminated hyperbranched polymer (HBP-NH2) was applied as a reducing agent to prepare nano silver. A suitable finishing process was proposed to treat polyester fabrics with nano silver solutions. The distribution and morphology of nano silver on the surface of polyester fiber were observed by SEM. EDS analysis was carried out to investigate element contents of the treated polyester fabrics. The FT-IR spectra, physical mechanical properties and antibacterial activities of nano silver antibacterial polyester fabrics had been tested and compared with common polyester fabrics. The results showed that nano silver particles dispersed uniformly on the surface of the fiber. The treated polyester fabrics attained excellent antibacterial activity and washing durability. The nano silver antibacterial polyester fabrics had an expansive application prospect.