Abstract: An air cooling structure of computer chassis includes: a first chassis, a second chassis, a third chassis, a computer motherboard, and a cooling fan; wherein, the first chassis, the second chassis, and the third chassis are provided in turn; the computer motherboard is provided in the first chassis, a CPU is provided on the side surface of the computer motherboard towards the second chassis, a peripheral interface is provided on the side surface of the computer motherboard far away from the second chassis, a cooling hole is provided on the second chassis, the cooling fan is provided in the second chassis, a graphics card is provided in the third chassis. Because of the openness and specific function of the middle-zone cooling system, the disclosure, the cooling becomes more efficient.