Abstract: Rex rabbit is a kind of economic animal, used for both meat and fur and its breeding environment can directly affect the production performance. For monitoring and assessing the breeding environmental indicators of rex rabbits in spring of Northern China, which environmental indicators were determined during April to May that including temperature, humidity, wind velocity, light, CO2 concentration and NH3 concentration of the breeding barn (air-tight type) in Wan Yuan Rex Rabbit Farm in Yushu, Jilin province. The diagonal method was adopted to select the measuring points. Six points including A, B, C, D, E and F in the horizontal direction and the high, middle and low points in the longitudinal direction were chosen. It was measured three times a day (7:30, 12:00 and 18:00) and lasted 21 days. The results showed that the temperature of the barn varied from 13.04 °C to 18.37 °C. The humidity was varied from 50.23% to 75.73%. The wind velocity varied from 0.05 m/s to 0.09 m/s. The light varied from 37.45 Lux to 137.37 Lux. The CO2 concentration varied from 0.12% to 0.22%. The NH3 concentration was 4.41-16.80 mg/m3. The results reflected that the humidity in some parts of the breeding rabbit barn was extremely high, the illumination in it was uneven and the NH3 concentration reached a dangerous level, which resulted in colds, pneumonia and diarrhea among the rex rabbit, in particular, the survival rate of pups was only 62.5%. Taking effective measures, such as increase ventilation, improve light regime and clean up feces in time etc. significantly enhanced the situation. The NH3 concentration reduced to 4.41 mg/m3. The humidity decreased by 3.2% to 7.1%. The abortion rate of rex rabbit significantly reduced by 13% and the overall incidence of illness for rex rabbit was significantly improved.