In this study, we prepared $TiO_2$ nanoparticles $(<~10nm)$ whose crystalline structure were predominantly anatase. However, during the pad-dry-cure process, many of the $TiO_2$ particles aggregated on the surface of nylon and PET fabrics. The antimicrobial activities and photocatalytic degradation properties of the Ti02 treated nylon and PET fabrics were analyzed and the results suggest that the $TiO_2$ promotes the degradation of the nylon and PET polymers.