NOVELTY - Method for preparing biomass charcoal adsorbent loaded with chitosan magnetic nanoparticles, involves (a) preparing biomass charcoal, (b) preparing a chitosan-acetic acid solution, (c) preparing an iron solution by dissolving ferric chloride and ferrous sulfate in water, and (d) mixing powdered charcoal biomass and chitosan-acetic acid solution to obtain mixed solution, adding mixed solution to iron solution, stirring uniformly, adjusting pH, heating mixture, allowing mixture to stand, performing solid-liquid separation, washing, and drying to obtain the product.    USE - The method is useful for preparing biomass charcoal adsorbent loaded with chitosan magnetic nanoparticles (claimed). The adsorbent is useful for absorbing heavy metal, dye and partial anions.    ADVANTAGE - The prepared adsorbent has high adsorption capacity, strong magnetism, stable property and high mechanical performance.    DETAILED DESCRIPTION - Method for preparing biomass charcoal adsorbent loaded with chitosan magnetic nanoparticles, involves (a) preparing biomass charcoal by drying biomass charcoal under natural conditions, crushing dried material, heating crushed material under anoxic conditions in sealed decentralized muffle furnace, allowing treated material to stand, cooling material, and crushing to obtain powdered charcoal biomass, (b) preparing a chitosan-acetic acid solution by mixing chitosan, glacial acetic acid and water, (c) preparing an iron solution by dissolving ferric chloride and ferrous sulfate in water, and (d) mixing powdered charcoal biomass and chitosan-acetic acid solution to obtain mixed solution, adding mixed solution to iron solution, stirring uniformly at room temperature, adjusting pH to 10-12 by adding cross-linked agent, heating mixture using microwave, allowing mixture to stand, performing solid-liquid separation, washing, and drying to obtain the product. An INDEPENDENT CLAIM is included for biomass charcoal adsorbent, which isobtained by using biomass charcoal as substrate, and adsorbent, where the surface of adsorbent is loaded with the chitosan magnetic nanoparticles.