Abstract: Abstract: The objective of this study is to analyse performance of a modified heat recovery ventilator in air conditioner cooling breeding rabbit house in hot season. The heat recovery ventilator was employ to reduce the energy consumption of cooling rabbit house, alleviate the contradiction between air conditioner cooling and ventilation. During the operation of the air-conditioner, air temperature in the rabbit house maintained 22-27 ℃ when the ambient air temperature varied 31-39 ℃. The heat recovery ventilator was used to reduce energy consumption of the air-conditioner. The experiment was carried out in two rabbit houses with heat recovery ventilator (treatment house) and without heat recovery ventilator (control house). Compared with the control house, the air temperature in the treatment house was higher by 1.4 ℃, while the NH3 and CO2 concentration in the treatment house decreased by 10% and 21%, respectively. The application of the heat recovery ventilator reduced 10.2% energy consumption of the air-conditioner during the hot season, and the sensible heat efficiency of the heat recovery ventilator was 63.3%. The heat recovery ventilator was economic to operate when the temperature difference between indoor and outdoor was more than 5.1 ℃. There is 501 h available time every year for the operation of the hot season in southeast China, and the calculated annual electricity saving was 4.6 kWh for every square meter of rabbit house. Pressure drop of the heat exchanger and the duct ventilation organization are potential factors for improving performance of the system.