Abstract: Objective: To establish an Ultraviolet Spectrophotometry method for the determination of ascorbic acid in theweiduokang.Method:Using Cu2+as the catalyst to accelerate the oxidation of VC EDTA .resmbling correction background ascomparison .By mean of easuring the difference ( A) of adsorbency before and after the oxidation to obtain the content of VC. Itshowed that there exists a maximum obsorption peak of reduction type VC at the position of 265.2nm.Results:The calibration curveof ascorbic acid was linear (r=0.99922) over the recovery is between 105.77%～109.50%.Conclusion:The method is sensitive,accurate, precision is high, can be applied to determine ascorbic acid in other preparations.

Key words: VC, ultraviolet spectrophotometry, weiduokang