A novel composite basing on the Fe3O4 nanoparticle, the graphite oxide nanosheet (GON), and the citric acid-crosslinked beta-cyclodextrin polymer (CA-CDP) was prepared for the purpose of removing the methylene blue (MB) dye from water. The structure of the resultant Fe3O4/GON/CA-CDP composite was investigated by the scanning electron microscope, the two dimensional EDS mapping, the thermal gravimetric analyzer, the Fourier transform infrared spectroscope, the wide angle X-ray diffraction, the X-ray photoelectron spectroscope, and the zeta potential measurement. The Fe3O4/GON/CA-CDP composite not only had a good MB adsorption capacity of 173 mg/g but also a high saturation magnetization of 36.4 emu/g. It was found that the MB adsorption capacity of the Fe3O4/GON/CA-CDP composite increased with the increasing initial MB solution pH value especially in the low-pH-value range. Moreover, the MB adsorption mechanism, the MB adsorption isotherm, and the MB adsorption kinetic of the Fe3O4/GON/CA-CDP composite were investigated. It was found that 1) the good adsorption ability of the Fe3O4/GON/CA-CDP composite for the MB dye originated from the electrostatic attraction, the Lewis acid-Lewis base interaction, the host-guest supramolecular interaction and the 7C -7C interaction, and 2) the MB adsorption isotherm and the MB adsorption kinetic of the Fe3O4/GON/CA-CDP composite could be well explained by the Sips model and the intraparticle diffusion model, correspondingly. (c) 2021 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.