Abstract: A gas chromatography (GC) method was developed for the determination of underivatized free fatty acid (FFA) and fatty acid methyl ester (FAME). Test results show that long/medium chain FFAs and FAMEs in sample could be separated by a single run, when using a CP-FFAP CB capillary column and with a heating procedure as follows: keep at starting temperature (180℃) for 0.5 min, using a heating rate of 3℃/min to reach 210℃, followed by heating to 250℃ with a rate of 10℃/min and keep for 30 min. The contents of every FFAs and FAMEs in the sample could also be determined accurately by employing two internal standards.