A method had been developed by Ion-pair RP-HPLC for simultaneous determination of eight water-soluble B vitamins(thiamine, riboflavin, niacin, pantothenic acid, pyridoxine, biotin, folic acid and cobalamin) in beer. The method had excellent linearity with the correlation coefficients over 0.9993. And its average spike recovery varied from 98.04 % to 103.27 % with RSD within the range of 0.32 %~1.26 %.