Abstract: RP-HPLC was applied to the simultaneous determinations of six B-group vitamins including vitamin B1,vitamin B2,vitamin B6,niacin,nicotinamide and pantothenic acid in functional drinks.The conditions of separation by liquid chromatography were tested and optimized.The Kromasil C18 column (200 mm×4.6 mm,5 μm) was used as stationary phase,and mixtures of methanol (A) and triethylamine solution (φ=0.3%,adjusted to pH 3.5 with H3PO4) (B) in different ratios were used as mobile phase in the gradient elution.UV-detections were used at the wavelength of 200 nm for determination of pantothenic acid and at 270 nm for the other 5 vitamin B′s.Linear relationships between the values of peak area and mass concentration of the six B-group vitamins were obtained in the range of 0.5~100 mg·L-1.The values of recovery found by standard addition method were in the range of 97.8%-106.2%,and values of RSD′s (n=5) were in the range of 0.5%-2.3%.