Photocatalysis has attracted great attention as a new method for wastewater treatment. However, in practical applications, particularly in environments with severe water pollution, the penetration of light into deeper layers is challenging, thereby restricting photocatalytic reactions mainly to the water surface. In addition, dispersed catalyst has the problem of residue and difficulty in separation. In this study, TiO₂ nanoparticles (NPs) adhered quartz and polydimethylsiloxane (PDMS) optical waveguides are proposed to address the aforementioned issues. By employing this approach, light can effectively reach the deep layers of wastewater, activating the TiO₂ NPs on the waveguide surface and facilitating the degradation of pollutants in these deep layers. On the other hand, TiO₂ NPs adhered on the waveguide surface reduce the likelihood of secondary pollution. Experiments have demonstrated that TiO₂ NPs adhered quartz optical waveguide and PDMS optical waveguide can degrade rhodamine B (Rh B) in its aqueous solution with a concentration of 1.04×10^-6 g/mL at degradation rates of 78.9% and 88.8%, respectively, after 10 hours of 365 nm UV irradiation. In the testing of heavily polluted water with Rh B carbon ink mixture, the TiO₂ NPs-adhered PDMS waveguide exhibits an averaged degradation rate of 63.1% after 10 hours of irradiation, which is approximately 2.21 times that achieved with a direct TiO₂ NPs-dispersed photocatalytic system. The preparation method of TiO₂ NPs-adhered waveguides is simple and cost-effective, and has wide application prospects in industrial wastewater and environment purification.