The methods for sampling and analyzing 10 carbonyl compounds such as formaldehyde, acetaldehyde, acrolein, acetone, propionaldehyde, crotonaldehyde, butyraldehyde, benzaldehyde, cyclohexanone, valeraldehyde in indoor air were proposed with the sampling efficiency, recovery and detection limit being 92% - 100%, 91% - 104%, 0.26ng/m3 - 0.82ng/m3, respectively. Pollution survey of 10 carbonyl compounds in air of 6 trains was conducted. It was indicated that the total concentrations of carbonyl compounds were 0. 1591 mg/m3 - 0.2828 mg/m3 with the average concentration of 0.2330 mg/m3, the average concentrations of formaldehyde, acetaldehyde and acetone were 0.0922 mg/m3, 0.0499 mg/m3 and 0.0580 mg/m3, accounted for 42.6%, 21.4%, 24.9% of the total carbonyl compounds' concentrations, respectively. The carbonyl compounds probably came from woodwork and tobacco. The intake of carbonyl compounds for the passengers was approximately 0.043 mg/h - 0.076 mg/h.