Abstract: A method of the simultaneous determination of the contents of nicotinic acid,lactic acid,citric acid,benzoic acid,salicylic acid in complex organic acids by RP-HPLC was established. The separation was performed on Agela-ASB C18 column （250 mm×4.6 mm,5 μm） with the mobile phase of hydrochloric acid solution （0.1 %,V/V,A）-acetonitrile （B） gradient elution. The detection wavelength was 210 nm. The flow rate was 0.7 mL/min and the column temperature was （30±2） ℃. Good linearities of formic acid,propanoic acid,lactic acid,maleic acid,citric acid,fumaric acid,benzoic acid were showed within the ranges of 100～2 000,100～2 000,100～2 000,2～40,100～2 000,2～40 μg/mL,2～40 μg/mL respectively,r 〉 0.999 5. The average recoveries were 99.1 %,98.6 %,100.1 %,98.8 % ,99.3 % ,99.5 % ,98.2 % respectively,RSD 〈1.5 % . The method was simple,rapid and reliable for the simultaneous determination of seven components in the complex organic acids.