The invention discloses suspended microbial packing for wastewater treatment and a preparation method thereof. The suspended microbial packing is prepared from, by weight, 65-75 parts of high density polyethylene, 5-15 parts of slaked lime, 5-20 parts of Dow powdered activated carbon, 6-10 parts of light calcium carbonate, 3-5 parts of maleic anhydride, 1.5-3 parts of gelatin, 1-2 parts of chitin, 0.8-2 parts of ferromagnetic oxide powder and 0.1-0.3 part of manganese zinc ferrite. The suspended microbial packing is high in film formation speed, not prone to fall off, high in treatment efficiency and suitable for treatment of low-concentration organic matter and ammonia nitrogen in sewage and low-concentration organic wastewater. The biological packing has the extremely high hydrophilicity and biocompatibility, has the very high adsorption strength to a biological film and is beneficial for interception and accumulation of biomass on a packing carrier, and therefore the packing can better adapt to wastewater treatment under the low concentration condition.