The invention discloses a sewage deodorization method. The method comprises the steps of sewage filtering, sewage precipitation and microorganism deodorization carried out on the sludge produced after precipitation. The method further comprises the steps that sludge containing microorganism flows back to sewage raw water and is mixed with the sewage raw water. According to the technical scheme, sludge containing microorganism flows back to sewage raw water and is mixed with the sewage raw water, sewage mixed with the microorganism carries the microorganism to all units of a sewage treatment system when passing through the units of the sewage treatment system. Bad smell of all the units of the sewage treatment system can be removed by means of the microorganism deodorization effect. The good deodorization effect can be achieved, no deodorization system needs to be added to the sewage treatment technology, and therefore investment cost and running cost of a sewage treatment plant are reduced.