The invention belongs to the technical field of biological filter fillers, and particularly relates to a method for preparing a biofilter filler nutritional agent from poultry manure, which comprises the following steps: (1) collecting poultry manure, conducting stirring and mixing, controlling the water content to be 50-55%, uniformly dividing the formed mixture into 5-10 parts by weight; drying and carbonizing biomass auxiliary raw materials, then adding a strain accelerant, uniformly conducting stirring and mixing, then adding 1 equal part of poultry manure, inoculating EM bacteria, uniformly conducting stirring, conducting standing for 48 hours, then adding 1 equivalent of poultry manure every two days until the poultry manure is completely added, and completing fermentation treatment; and (2) adding ammonium sulfate, ferrite, sodium bicarbonate, starch and persulfate into the fermented product, and uniformly conducting stirring and mixing to obtain the filler nutritional agent for a biological filter. The nutritional agent provided by the invention promotes adsorption, stationing and propagation of bacteria and microorganisms on the filler of the biological filter, so that the formation rate of a biological membrane is promoted, and biological treatment of sewage is realized at a relatively high speed.