In this paper, ethyl-bridged periodic mesoporous organosilica (PMO) is modified with β-Cyclodextrin (β-CD) using “grafting” method. As a contrast, β-CD modified mesoporous silicas SBA-15 is synthetized by the same method. Functionalized mesoporous PMO materials was characterized by Fourier transform infrared (FTIR) spectroscopy, high-resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (XRD), nitrogen adsorption–desorption measurements and thermogravimetric analysis (TGA). The adsorption properties of the pollutants in water, phenylamine and p-benzenediol, are investigated. For β-CD modified ethyl-bridged periodic mesoporous organosilica (PMO-CD), the results show that the adsorption quantity of phenylamine was 1.54 mg/g, which was reduced due to the β-CD modification comparing with PMO. But the adsorption quantity of p-benzenediol was 12.94 mg/g, which was improved greatly. Therefore, PMO-CD has the potential applications in the treatment of the water pollutants.