Abstract: Objective: To improve the sample processing method of vitamin B12 tablets content determination.Methods: Take vitamin B12 55 pieces,make 1 ml solution contain about 12.5 g vitamin B12.Detect the absorbance by UV spectrophotometry with the wavelength of 361 nm.Results: When vitamin B12 content was in the range of 1.25-25.00 g / ml,it had a good linear relationship(r = 0.999 9),the minimum detectable concentration was 1.25 g / ml,a good solution stability and the relative standard deviation of 0.5%.Using the standard method,the sample concentration was 102.06%,102.35% and 102.00%,but the result was 101.59%,101.86% and 101.42% with the improved method.Conclusions: Comparing with the standard method,the improved method can reduce the amount of splitting,decrease the sample concentration,improve the detection accuracy,shorten the analysis time.It can be used for content determination of vitamin B12 tablet.