The structure of hexagonal boron nitride (h-BN) is similar to that of graphite, which has strong reducibility and adsorbability. In this study, boron nitride precursor was made using melamine as a nitrogen source and boric acid as a source of boron under hydrothermal conditions, and the precursor was subsequently burned to create porous BN at a certain temperature. Effect of NH4HCO3 content on the porosity and structure of the materials was investigated to improve the adsorption performance of h-BN. The morphology, composition and structure of the materials were analyzed by scanning electron microscope, energy spectrum analyzer and X-ray diffraction. According to the findings, BN has a greater specific surface area of 169.29 m2/g under optimal preparation circumstances, which increases its capacity for adsorption. When the concentration of methylene blue was 200 mg/L, the adsorption capacity of the material reached to 377 mg/g in 120 min. In addition, the remarkable anti-oxidation and structural stability of the employed BN materials make it simple to regenerate them through burning or ethanol elution. In five cycles, the adsorption performance did not decrease.