Abstract: The organic acids in TPM of mainstream cigarette smoke were extracted with dichloromethane, then derived with N, O-Bis(trimethylsilyl) trifluoroacetamide, and 30 organic acids, including formic acid, acetic acid and eibcosanic acid, were simultaneously determined by GC/MS with precolumn and SIM mode, using trans-2-hexenoic acid and cinnamic acid as double internal standards.The recoveries of the method ranged from 74.3% to 101.8% and the RSDs were all below 9.8%.The acidic constituent contents in TPM of 10 domestic flue-cured type cigarette brands were also presented, this method was suitable for rapid analysis of volatile and semi-volatile organic acids in TPM of a batch of cigarettes.