A novel ultrasonic atomization bioreactor was designed to improve the removal effect of the bioreactor on the odor produced by composting. The treatment effect of the bioreactor on simulated odor under different conditions was studied. The pig manure and wood chips were used to conduct composting experiments to explore the actual effect of the bioreactor on removing odor produced by. The results showed that the effect of ultrasonic cavitation improved the absorption rate of ammonia gas. Ultrasonic atomization was about 10% more efficient than the traditional spray mode in removing ammonia gas. In order to solve the problem of high ammonia nitrogen in the system， the activated sludge was domesticated with high ammonia nitrogen and hung in the reactor， and the ability of microorganisms in the system to degrade ammonia nitrogen was significantly improved. The process conditions for removing ammonia gas with the bioreactor were optimized with orthogonal experiments. The results of composting experiments showed that ammonia release was highly consistent with the temperature of composting and peaked on day 5 of composting （76.3 mg/m³）. The ammonia release in pig manure composting was related to the pH， the concentration of ammonium nitrogen and nitrate nitrogen. The reactor’s removal rate of composting ammonia peak was 80.6%， the average ammonia removal rate for other periods was maintained at about 90%. The ammonia concentration at the outlet of bioreactor was less than 5 mg/m³， which meets the relevant emission standards. It is indicated that the ultrasonic atomization bioreactor can play a good role in removing ammonia gas produced by composting. It will provide a new idea for developing bioreactors in the future.