The invention discloses an air purification device. The air purification device comprises an air volume regulation mechanism used for regulating the volume of fresh air entering a box body from a fresh air port and regulating the ratio of the volume of return air entering the box body from an air return port to the total air supply volume according to the indoor gas concentration parameters. The invention further discloses a control method of the air purification device. On the basis of purifying indoor air, the air purification device supplies outdoor fresh air with high oxygen content appropriately according to the indoor oxygen content change, and the influence of loads caused by temperature difference between the indoor air and the outdoor air can be lowered to the maximum degree. The air purification device has the advantages of being safe and convenient to use and saving the energy.