The utility model discloses an air treatment system. The air treatment system comprises a cleaning room, an upper interlayer, a lower interlayer and a return air vertical shaft, wherein the upper interlayer is located above the cleaning room, and the lower interlayer is located below the cleaning room. Equipment which will emit chemical substance pollutants can be placed inside the cleaning room. The lower interlayer and the cleaning room are separated through a separation board system provided with a return air port. The lower interlayer comprises a lower layer enclosure and a chemical substance pollutant treatment device, wherein the lower layer enclosure extends from the top of the lower interlayer to the bottom of the lower interlayer and is located below an area for containing the equipment which will emit chemical substance pollutants, and air inside the cleaning room can enter the lower layer enclosure through the return air port of the separation board system; the chemical substance pollutant treatment device is located inside the lower interlayer and is communicated with the space defined by the lower layer enclosure through a pipeline. Air treated by the chemical substance pollutant treatment device can enter the upper interlayer through the return air vertical shaft. The air treatment system solves the technical problems that due to the fact that all the circulation air inside the cleaning room needs to be treated by the chemical substance pollutant treatment device, the amount of the air needing to be treated is large, and the treatment efficiency is low.