Abstract: In order to improve the internal environmental quality and thermal insulation of the poultry house in cold winter climate, an internal circulation environmental control system was installed in the laying hen house in the experiment. The system mainly consisted of internal circulation control devices, exhou ducts, ducts and ventilation holes.By changing the diameter and number of ventilation holes on the air inlet pipe and the inlet wind speed of the air inlet pipe, and the CFD simulation software for computational fluid dynamics was used to simulate the airflow inside the laying hen house.The distribution of the airflow through the pipe was analyzed in the poultry house. The measured values were compared with the simulated values CFD and the accuracy of simulation results was verified. The results showed that the average relative error of the wind speed between the measured and CFD values was 12.42%, and the average absolute error was 0.07 m/s.When the diameter of ventilation holes was 47 mm and the number of ventilation holes was 32,environmental regulation was the most appropriate. At this time, the inlet wind speed was 4 m/s; the area of the comfort zone（0.1 m/s＜wind speed in the laying hen house＜0.8 m/s） accounted for 82.21%, and the average speed was 0.52 m/s. The results indicated that the internal circulation environmental control system and the pipes designed in this study were conductive to improve the environmental control and thermal insulation of poultry houses in winter climate, and also ensure the uniformity of air distribution.