A physical model of a tall space livestock house was established using Prosim software and the relevant boundary conditions were set under the replacement of ventilation conditions. The exhaust air volume calculated by different ventilation times is simulated to the effort of the indoor pollutant concentration distribution and the measuring points are evenly arranged in the space. The study found that the replacement ventilation effect is optimal and the indoor pollutant concentration is the lowest when the indoor air supply and exhaust air volume are increased to 45 times/h.