The invention belongs to the technical field of analytical chemistry and relates to a preparation and application method of a nickel ion imprinted magnetic chitosan nanometer material. The nickel ion imprinted magnetic chitosan nanometer material is prepared by taking ferroferric oxide as a carrier, Ni2+ as a template and chitosan as a functional monomer and is prepared by steps: synthesizing ferroferric oxide chitosan according to a one-step method, adding Ni(NO3)2 aqueous solution to form a complex, adopting epoxy chloropropane and sodium tripolyphosphate for crosslinking by stirring ultrasonically at the temperature of 60 DEG C under the protection of N2, adopting EDTA-Na solution for oscillating elution of template ions, cleaning, drying and grinding. The preparation process is simple, quick and reliable, and the prepared material is not only specific in Ni2+ recognition but also has superparamagnetism. After the material is added into environmental water samples or other sample solutions containing Ni2+, Ni2+ can be enriched by stirring for 10min, and quickness in solid-liquid phase separation can be realized by the aid of an external magnetic field. The recovery rate is higher than 4% by adoption of the 5% EDTA-Na solution for elution of adsorbed Ni2+. The method is high in selectivity, and the material can be reused for 5-6 times.