: Due to the compact structure and water repellent nature of polyester, it is necessary to use high temperature and pressure for dyeing which produce large amount of waste water. In this study, colorants free coloration as a novel method for polyester fabrics through titanium dioxide nanoparticles as photocatalysts and H2O2 under UV irradiation was investigated. The colored samples were analyzed through spectral data and coloring parameters. The mechanisms of coloration were proposed using FTIR analysis. For evaluating the influence of surface modification on moisture absorption, the time of drops absorbance by sample, wicking and contact angle tests were done. ATR-FTIR and SEM images were used to investigate the changes in the chemical and physical structure of polyester. Tensile strength and bending properties of samples were measured. Wash and light fastness were evaluated. K/S values and color differences of modified samples confirmed that the H2O2/UV modification method had the most impact on the color changes of samples with the color of white to brilliant kelly color. FTIR results confirmed the substitution of –OH groups on the aromatic rings, dissociation of polymer chain due to the H2O2/UV treatment, resulting in free carboxylic acid groups along with a decreased in amorphous region by TiO2/UV treatment. SEM images show corrosion and existence of the titanium dioxide nanoparticles on the modified surface. The results obtained from H2O2/UV treatment revealed that this method had better influence on the flexural properties in comparison to other methods. Result indicated that the modified samples have lower mechanical strength than the untreated sample. Also, the wash and light fastness of modified polyester fabrics were similar to that of untreated polyester fabric. Keywords : Titanium Dioxide Nanoparticles; photocatalyst; H2O2; Colorants Free Coloration; UV Irradiation; Polyester