The invention relates to the technical field of external medicine compositions for pets, in particular to a deodorization spray for pets and a preparation method thereof. The deodorization spray for pets is prepared from, by weight, 3-10 parts of composite biological enzyme, 0.01-20 parts of surfactant, 5-20 parts of plant extract, 0.01-5 parts of plant essential oil and 55-95 parts of pure water. The deodorization spray for pets has the three highlights of bacteriostasis, deodorization and mild parasite expelling; compared with existing products on the market, the deodorization spray has the advantages that the deodorization spray is good in antibacterial effect, the removal rate of escherichia coli, pseudomonas aeruginosa and staphylococcus aureus can reach 99%, the deodorization effect is better, and the removal rate of hydrogen sulfide, sulfur methoxide and ammonia in dog excrement can reach 86% or above; by adopting the non-toxic harmless compound biological enzyme, the natural plant extract without special peculiar smell, the surfactant with a good sterilization effect and the mild essential oil with an insect expelling effect, the pet deodorant is easier to accept by pets while effectively inhibiting bacteria and deodorizing, cannot cause pet stress reaction, is stable in chemical property, has no side effect, meets the requirements of environmental protection, and is suitable for popularization and application.