Abstract: Reverse-phase high performance liquid chromatography was applied to the determination of benzoic acid,sorbic acid,acesulfame K,sodium saccharin and aspartame in foodstuffs. The sample was extracted with water ultrasonically,the extract was separated on ODS-3 column,and eluted with a mixed solution of acetonitrile and 20 mmol·L-1 KH2PO4 solution as mobile phase by gradient elution;UV-detections at 210 nm for sodium saccharin and aspartame and at 230 nm for the other 3 compounds were used in the determination. Linear relationships between peak area and concentration of the 5 compounds were obtained in the range of 10-200 mg·L-1 for all of them. Tests for precision and recovery were performed and results were given in the paper.