The nanocomposites of TiO2 doped with different Ag contents were prepared by hydrothermal process, and PANI/Ag-TiO2 fibrous nanocomposites were synthesized via in-situ polymerization. The structures of products were characterized by the detection techniques including XRD, SEM and FT-IR. The effects of light source, Ag doping content and types of bacterias on the antibacterial activity of PANI/Ag-TiO2 fibrous nanocomposites were investigated. The results show that the PANI/Ag-TiO2 fibrous nanocomposites have excellent antibacterial activity under the dark light, which is further improved under long-wave UV condition. With the concentration of 1 mg/mL, the sterilization rate to 4 kinds of bacterias of the PANI/Ag-TiO2 nanocomposites can reach 99.99% averagely under the dark light.