A vinegar beverage combined with purple sweet potato and bitter buckwheat was developed, and the flavor compounds in it were analyzed. Purple sweet potato and buckwheat were processed through smashing, size mixing, saccharification, alcoholic fermentation and acetic fermentation to produce brew purple sweet potato and buckwheat vinegar, respectively.. The optimum formula of the vinegar beverage was obtained through single factor and orthogonal experiments. The 100 mL optimum complex contained 4 mL purple potato vinegar stock solution, 4 mL buckwheat vinegar stock solution,4 g saccharose, and 4 g fructose-glucose syrup. The vinegar beverage prepared under this condition had a unique purple potato and buckwheat vinegar flavor which was red bright, sweet and sour. Seven organic acid including acetic acid, citric acid, acetic acid, lactic acid, etc. and 14 kinds of flavor substances such as benzene alcohol, benzene formaldehyde, acetic acid benzyl ester, etc. were detected, by using High Performance Liquid Chromatography and Gas Chromatography-Mass Spectrometer in this vinegar beverage.