Abstract:A rapid method for determination of vitamin C in colorful potato species Solanum tuberosum black beauty and red ruby was established by high performance liquid chromatography（HPLC）. Vitamin C in potatoes was extracted by 2 % oxalic acid， then separated through a C18 chromatographic column with the phosphoric acid - methanol buffer （0.05 mol/L，pH2.5） as the mobile phase. Thereafter， the vitamin C was detected by ul traviolet-visible detector at the wavelength of 245 nm. The absorbance in samples was compared with the standard substance， which qualitative determination was according to the retention time， and quantitative determination was according to the peak area. The results showed that the linear range of the present method was 0.02 g/L-0.1 g/L， the detection limit was 0.002 g/L， and the linear equation was yb =5 622 000x + 69 538， the related co－ efficient was 0.999 9. After the recovery experiment， the recoveries were 97.61 %-99.81 %， 97.28 %-99.82 %， respectively， and the relative standard deviation were 0.90 %，1.02 %，respectively. The VC content in black beauty was（21.27±0.19），（19.92±0.13），（23.31±0.11） mg/100 g by HPLC， UV spectrophotometry， Iodomet－ ric method， respectively. And （18.28±0.19），（17.68±0.14），（21.76±0.09） mg/100 g in red ruby， respectively.Compared with the results from agricultural test center of Gansu academy of agricultural sciences（21.73 mg/100 g in black beauty；18.74 mg/100 g in red ruby）， the results of HPLC was preciser than the other two methods. The method can well be applied in the determination of vitamin C content with the features of rapid， sensitive， exact and stable， and applicable to detection of vitamin C in fruits and vegetables， such as strawberry， roxburgh rose and green vegetables.