A novel composite photocatalyst with hydrophobicity, modified Sr/TiO2-PCFM (porous ceramic filter media), was synthesized and characterized by applying X-ray fluorescence (XRF), scanning electron microscope and energy dispersive spectroscopy (SEM/EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), the Brunauer-Emmett-Teller (BET) method, Fourier transform infrared (FTIR) spectroscopy and UV-visible diffuse reflectance spectroscopy (UV-vis DRS). The results showed that the composite photocatalyst possessed a pure and highly crystalline anatase TiO2 layer and large specific surface area. The photodegradation of acephate by Sr/TiO2-PCFM was investigated under various conditions, e.g., the adsorption time, initial acephate concentration, Sr/TiO2-PCFM dosage, and pH. The acephate-preferred photocatalytic performance of the modified Sr/TiO2-PCFM with hydrophobic characteristics was explored for the first time in this study. The results revealed that the photocatalytic degradation process for the modified Sr/TiO2-PCFM preferred acephate over methylene blue (MB) in the acephate/MB mixture under ultraviolet light irradiation. The underlying mechanisms of the preferential degradation process of modified Sr/TiO2-PCFM was also studied. The results indicate that the modified Sr/TiO2-PCFM is a promising candidate for the preferential degradation of refractory organic matter in organophosphorus pesticides contaminated wastewater.