To determine the content of loganin and sarsasapogenin in Zhibai Dihuang Pills by HPLC.Methods:The chromatographic conditions were determined by C18 column(type Eclipse XDB).The length of the column was 250 mm，the diameter of the packing particles in the column was 5 micron，and the inner diameter of the column was 46 mm.A binary system of acetonitrile(A phase）and 01% phosphoric acid aqueous solution(B phase）was used for gradient elution.The method of high performance liquid chromatography(HPLC）was rigorous，including linear relationship，precision，repeatability，stability and sample recovery test.Based on the rigorous premise of HPLC，the content of Zhibai Dihuang Pills was determined.Results:1）Negative reference solution 1 did not show the same chromatographic peak at the same time as loganin reference solution and test solution，while negative reference solution 2 did not show the same chromatographic peak at the same time as sarsasapogenin reference solution and test solution.The results showed that loganin and sarsapogenin had good specificity. 2）Linear regression equation，correlation coefficient and linear range were：loganin had good linear relationship with peak area in the range of 0040 54~4054 μg，and the regression equation was Y=61116X+5 6641(r=0999 7); sarsapogenin injection was 044 ugh，and the regression equation Y=1639 7X+11549(r=0999 8）was obtained. 3）The precision test showed that the RSD was 079%.The stability test showed that the RSD average value of the relative peak area was 1716%.It indicated that the stability of Zhibai Dihuang Pills was good within 24 hours.The value was 2011%，indicating that the solution of Zhibai Dihuang Pills had good reproducibility. 4）The results showed that the average recoveries of loganin and sarsapogenin were 105719% and 98865% and RSD were 129% and 136% respectively，suggesting that the high-phase liquid phase detection method was reliable. 5）The contents of strychnine and sarsapogenin in Zhibai Dihuang Pills of different batches，such as 201805026，201806013 and 201807085，were not significantly different.Conclusion:The HPLC method is simple，accurate，stable and reproducible.It can be used as an effective method for quality control of Zhibai Dihuang Pills.There was no significant difference in the content of active ingredients in different batches of Zhibai Dihuang Pills.