The distribution of the temperature field， relative humidity field， and airflow velocity field in the current layer house was simulated with computational fluid dynamics （CFD） to optimize the thermal environment in a closed cage-rearing layer house under the mode of vertical ventilation in autumn. The accuracy of the numerical model was verified. The average THVI （temperature-humidity-velocity index） and coefficient of variation （CV_THVI） of the cage-rearing areas were calculated for the parameters of ventilation equipment including the angle of the guide plate at the front mountain wall tunnel inlet（θ₁）， the angle of the guide plate at the side wall tunnel inlet（θ₂） and ventilation volume of a suction fan at the end（Q） at three different levels by conducting 17 sets of orthogonal simulation experiments. The results showed that the average relative error of temperature， relative humidity， and airflow velocity at the 24 verification points set on the aisle of cage was 0.38%， 0.52%， and 4.62%， respectively， indicating that the accuracy of the numerical model is high. When the parameters of ventilation equipment θ₁，θ₂ and Q were set to 10°，90° and 42 000 m3/h， the average THVI and coefficient of variation CV_THVI of the airflow field in the cage-rearing areas was 25.65 and 1.64%， 1.61% and 23.93% lower than that of the original scheme of ventilation， beneficial for improving the suitability and balance of the thermal environment in the cage-rearing areas of the layer house.