NOVELTY - Preparing ammonia-oxidizing bacteria immobilized biological active filler involves: putting carrier to polyurethane foam high molecular material, screening culture of ammonia oxidizing bacteria in a suspension centrifugal concentrate, obtaining ammonia oxidizing bacteria concentrate liquid to 108-109 ml, mixing liquid and polyethylene alcohol solution, and adding calcium carbonate, polyvinyl alcohol mass concentration is 30-50 g/l of calcium carbonate, re-extruding embedded liquid, adjusting using boric acid pH to 8-10, cleaning residual surface, and cutting.    USE - For preparation of ammonia-oxidizing bacteria immobilized biological active filler.    ADVANTAGE - The preparation of ammonia oxidizing bacteria immobilized biological activated filler not only solves the problem that the ammonia oxidizing bacteria is difficult to establish and easy to lose, but also increase the reactor processing capacity, shortens the starting time, and it has wide application prospect.    DETAILED DESCRIPTION - Preparation of ammonia-oxidizing bacteria immobilized biological active filler of polyurethane carrier involves: putting carrier to polyurethane foam high molecular material is embedded carrier to municipal sewage plant sedimentation surplus sludge is a source, the rear screening enriching culture of ammonia oxidizing bacteria a suspension centrifugal concentrate, obtain ammonia oxidizing bacteria concentrate liquid of 108-109 ml, mixing ammonia-oxidizing bacteria concentrate liquid and polyethylene alcohol solution, and adding calcium carbonate to prepare embedding liquid, polyvinyl alcohol mass concentration is 30-50g/L of calcium carbonate, mass concentration is the embedding liquid into whole piece to block in polyurethane foam, re-extruding the embedded liquid entering into polyurethane foam, putting saturated boric acid solution to 3 hours rear, adjusting boric acid solution at pH to 8-10 cross-linking for 3-24 hours, taking out, cleaning the residual surface, and cutting.