BiOI nanosheets with high sorption capacity were successfully prepared by the simple hydrothermal method followed by calcination. The features of the as-obtained BiOI nanosheets were characterized by X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and specific surface area analyzer (BET). BiOI was used as an adsorbent to explore its sorption properties of benzidine by changing initial concentration, pH and time. Results showed that BiOI had high sorption activity for benzidine, and it was found that the BiOI in this paper exhibited higher sorption capacity than traditional BiOI, which could be mainly attributed to the large specific surface area of the sample and the existence of unsaturated sites in the sample. Meanwhile, the optimal sorption conditions were explored, the actual maximum sorption capacity of BiOI could reach 66.67 mg/g. In addition, the synthesized sample\'s reusability without obvious deterioration in performance was demonstrated by five cycles. The sorption process was in accordance with the Langmuir model and the pseudo-second-order kinetic model.