Abstract: The nickel hexacyanoferrate (KNiFC) compound is often applied for the ion adsorption of cesium and strontium in low-level radioactive wastewater treatment. In this work, the co-precipitate method was used for the preparation of KNiFC using K₄Fe(CN)₆ and Ni(NO₃)₂ as raw materials. Then this compound was added into the aqueous solution of CsCl with a certain molar ratio. The mixture was shaken with an oscillator for completely adsorbing cesium ions in KNiFC. The morphology, structure, adsorption stoichiometry and molar ratio of KNiFC before and after cesium ion adsorption were analyzed with transmission electron microscope (TEM), atomic adsorption spectrophotometer (AAS), X-ray diffraction (XRD), X-ray fluorescence (XRF) and Mossbauer spectrum. The results indicate that the obtained KNiFC has a 15-20 nm crystal size and ellipsoidal shape. Cs⁺ is adsorbed mainly by exchanging with the K⁺ in KNiFC. The phase structure of KNiFC is obviously changed after adsorption, but still maintains a good symmetry.