This work focused on the chemisorption of volatile organic compounds (VOCs) on particulate matter of less than 2.5 mu m (PM2.5). The detection results illustrated that VOCs on PM2.5 containing hydroxyl, carbonyl, and ester groups and CxHy on PM2.5 were sequentially decreased as 70.02, 21.35, 6.42, and 2.21%, respectively. The chemisorption mechanism showed that the stronger the electronegativity of oxygen-containing functional groups of VOCs, the easier it is to adsorb them on the silicate PM2.5 due to hydrogen bond formation. Strong electronegative oxygen-containing functional groups readily interacted through hydrogen bonds with silanol groups, which was the main component of PM2.5, resulting in VOC adsorption on PM2.5. Negative air ions (NAIs) can weaken the offset ability of the lone pair of electrons in oxygen-containing functional groups in VOCs, which could significantly weaken the possibility of forming hydrogen bonds with silanol groups. Therefore, NAIs can effectively inhibit the adsorption between VOCs and PM2.5, leading to a significant reduction in VOCs on the surface of PM2.5.