利用Ｈａｎｔｚｓｈ反应使庆大霉素形成二氢吡啶衍生物，应用一阶导数光谱法测定硫酸庆大霉素制剂的含量，以３４６．５ｎｍ波长处谷的振幅值作为庆大霉素的定量信息，在７８～３１３μｇ／ｍｌ范围内求得回归方程Ｄ＝－８．６１５×１０￣（－３）Ｃ＋１．５３１×１０￣（－４），相关系数ｒ＝０．９９９８，平均回收率为１００．５１％，变异系数为１．４９％，ｎ＝５。（回归方程中浓度Ｃ换算成ｕ／ｍｌ，由庆大霉素效价） Hantzsh reaction was used to make gentamicin into dihydropyridine derivatives. The content of gentamicin sulfate was determined by first-order derivative spectroscopy. The amplitude of valley at 346.5nm was used as the quantitative information of gentamicin. The regression equation D = -8.615 × 10 ~ (-3) C + 1.531 × 10 ~ (-4) was obtained in the range of 78 ~ 313μg / ml, the correlation coefficient was 0.9998, the average recovery was 100%. 51%, coefficient of variation was 1.49%, n = 5. (Regression equation concentration C converted into u / ml, by the price of gentamicin)