Abstract: In order to simulate the formation of small carbonyl compounds in aerosols from e-cigarettes, the proportions of propylene glycol (PG), glycerol and water in e-liquid samples were analyzed, and the main pyrolysis products of PG and glycerol in air atmosphere were investigated by pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS). The effects of heating temperature and moisture content on the formation of small carbonyl compounds from pyrolysis of PG and glycerol were studied. The results showed that: 1) The total contents of PG, glycerol and moisture accounted for 86.5%-93.2% of the e-liquid mass of 10 e-cigarettes, wherein moisture content accounted for less than 10%. 2) The yields of formaldehyde, acetaldehyde, acrolein, propanal, and acetone from pyrolysis of PG and glycerol increased gradually with the raise of temperature, and those increased first and then decreased gradually with the increase of moisture content.