The invention relates to a method for preparing nicotinamide, in particular to a method for preparing nicotinamide by immobilizing corynebacterium propinquum with a composite material, which belong tothe field of biotechnology. The method comprises the following steps: mixing polyvinyl alcohol and polyethylene glycol with water, heating a mixture and stirring the mixture, and fully dissolving themixture to obtain a PVA-PEG hydrogel, then adding diatomite and activated carbon, fully stirring the materials, and cooling the materials to room temperature to obtain the composite material for immobilization; then adding the thalline to-be-immobilized (wet thalline) to the composite material for immobilization to prepare PVA-PEG small round droplets, through drying and repeated expanding in a Na2SO4 solution, collecting the immobilized small discs, and washing the material with water, and performing cryopreservation; and adding a substrate 3-cyanopyridine to obtain the product nicotinamideafter the reaction. The method of the invention has small damage to microorganisms, high mechanical strength of the immobilized cells, long service life, small environmental pollution, simple separation and purification, and high product purity, and is suitable for large-scale industrial production.