Abstract: High temperature in summer has serious influence on rabbit production in China because of lack of effective cooling techniques in rabbit house. The application of evaporative cooling techniques is restricted in the area with climate of high temperature and high humidity in summer. Water conditioner system is a non-evaporative cooling system which use the underground water as the cooling medium. We evaluated the cooling effect of water conditioner on the thermal environment of open rabbit house, in which cooled air from the water conditioner system was delivered to doe cages through pipes. The results showed that the temperature inside the cages in the experimental rabbit house cooling with the water conditioner system was 2.5~3.3℃ lower than that of the control rabbit house without any cooling facilities (P<0.05), while the relative humidity inside the cages was 8% higher than the control at 14 o’clock. The air speed inside the cages of the experimental rabbit house varied from 0.7 to 1.4 m/s, and Temperature-Humidity Indexes (THI) inside the cages ranged from 25.5 to 29.0, which were 1.4~2.9 lower than the control (P<0.01), this indicated that the thermal environment was significantly improved. The doe panting decreased at noon in the experimental house. The water conditioner cooling system may alleviate the heat stress of the does in pregnant or lactating stage through improving the thermal environment inside cages, and is practicable for cooling open rabbit house in summer.