Our novel photo-activated ClO2 • oxidation method was applied to PP NWFs for the first time. The oxygen functional groups, including carboxy groups, were introduced to PP NWFs effectively by the oxidation method than the plasma treatment. β-CD was supported on photo-oxidized PP NWFs with ester bonds via a coupling reaction using EDC and DMAP. The prepared β-CD/PP NWFs composite showed guest inclusion ability in the dyeing test and sustained release of diclofenac sodium over 12 h in the phosphate buffer. This sustained slow drug release property was also observed in second attempt. This oxidative surface modification method is simple and can effectively introduce a carboxy group to a complicated threedimensional structure, such as NWFs. This method is useful for the subsequent functionalization of materials in various forms.