In order to study the influence of air inlet type on air age and CO2 of pig house, computational fluid dynamics (CFD) technology was used to simulate the wind speed, air age, CO2 and the convective heat transfer of pigs in an experimental pig house. The angle of the air inlet deflector of the original model (scheme A) was 50°, and the inlet height was 1.8m. At the same time, totally six additional inlet conditions were selected to simulate and compare the pig house with the original pig house. Scheme B: the angle of the air inlet deflector was 90°, and the inlet height was 1.8m; scheme C: the air inlet deflector angle was 120°, and the inlet height was 1.8m; scheme D: the air inlet deflector angle was 150°, and the inlet height was 1.8m; scheme E: the air inlet deflector angle was 50°, and the inlet height was 1.6 m; scheme F: the air inlet deflector angle was 50°, and the inlet height was 1.4m; scheme G: the air inlet deflector angle was 50°, and the inlet height was 1.2m. The results showed that the correlation R2 between the simulated and the measured wind speed value was 0.9162, and the average relative error was 26.7%. This model can accurately predict the airflow pattern in the pig house. Through the comparison of the simulation results of different air inlet deflectors, the scheme C and scheme F can significantly reduce the average air age and average CO2 concentration of pigs in the house, and maintain the heat preservation effect of the pig house. Comparing various air intake schemes, it can be found that the CO2 concentration in the animal occupied zone (AOZ) was not only affected by the average air age in the zone around the pigs, but also by the uniformity of the air age distribution throughout the entire pig house.