The invention discloses a biological deodorant and a preparation method thereof. Biological deodorants include the following raw materials: biological enzymes, anaerobic flora, aerobic flora, plant extracts, enzyme liquids, purification factors, volcanic mud, titanium dioxide fibers, acidic silica sol, azodicarboxylate Isopropyl ester, precious metal active ingredient. The biological deodorant of the present invention has the advantages of long deodorization time, high removal efficiency, quick effect, comprehensive and thorough removal effect on the odor of livestock farms, sewage around farms, urban sewage, garbage dumps, sludge, etc. A variety of odor-causing substances can be purified and absorbed, can repel mosquitoes, antibacterial and antibacterial, and can also remove and purify formaldehyde, toluene and TVOC emitted from wastewater discharged from organic synthesis, synthetic fibers, dyes, wood processing and other places Effect, the advantages of reducing damage to the human body.