The invention discloses an avian compound ofloxacin injection and a preparation method thereof, which aims at providing the avian compound ofloxacin injection that has rapid onset of action for the treatment for avian colibacillosis, effectivity, high efficiency and can ease the diseased avian stress reactions, treat both manifestation and root cause of disease, reduce the times and dosage of drug for being taken and reduce occurrence of the residual drugs exceeding the standards, and the preparation method that has simple technology and easy realization. Each 100l injection contains: 0.5 to 5kg of the ofloxacin, 3 to 15kg of neomycin sulfate, 0.2kg of sodium bisulfite, 500 to 2000ml of hydrochloric acid, 0.01kg of EDTA-2Na and 0.06kg of dexamethasone sodium phosphate. By adopting a compound preparation which combines anti-bacterial drugs and antibiotics for usage, and the combining usage of the ofloxacin, the neomycin sulfate and the dexamethasone sodium phosphate, the injection of the invention has rapid onset of action for avian colibacillosis, effectivity and high efficiency and can significantly ease the clinical symptoms caused by avian colibacillosis, treat both manifestation and root cause of disease, prevent the secondary infection and increase the weight of birds.