Semi-volatile organic compounds (SVOCs) are ubiquitous contaminants in indoor environments that may have significant adverse effects on human health. This study investigated photocatalytic reaction behavior of Di-2-ethylhexyl phthalate (DEHP), a kind of typical semi-volatile organic compounds (SVOCs) with high boiling point (386.9 degrees C) and high molecular weight (390.56), over the surface platinized TiO2. The oxidation state of platinum (Pt) was found to be the most important factor in determining the photocatalytic activity of DEHP. Platinized titania with oxidized Pt species (PtOx/TiO2) showed significantly higher photocatalytic activity than titania platinized with metallic Pt (Pt-0/TiO2). 1 wt% PtOx/TiO2 illustrated superior photocatalytic activity among the group of PtOx/TiO2 when substrate concentration reached at 1 %wt. Photocatalysis coupled with thermal catalysis could further strongly promote the degradation of DEHP. The Time-resolved PL indicated that photoexcited charge carrier lifetimes are longer for the PtOx/TiO2 compared with Pt/TiO2, highlighting the beneficial effects of Pt oxide, especially PtO, in promoting the separation efficiency of photo generated carriers and further improving the photocatalytic oxidation of DEHP. This work provides a facile methodology to investigate the photocatalytic reaction of SVOCs over photocatalyst which proved the validation of photocatalytic oxidation as a possible strategy to remove SVOCs from indoor atmosphere.