OBJECTIVE： To improve the detection method for the dissolution of dihydroartemisinin in Dihydroartemisinin and piperaquine phosphate tablets. METHODS： The dissolution experiment adopted paddle method using 0.1 mol/L hydrochloric acid solution 500 mL as solvent with rotating speed of 75 r/min and sampling time of 45 min. In sample pre-treatment， the volume of 3.6％ sodium hydroxide solution was increased from 5 mL to 20 mL， and that of phosphoric acid was increased from 0.2 mL to 0.7 mL. HPLC was adopted to determine the dissolution of dihydroartemisinin. The determination was performed on YMC-Pack ODS-A column with mobile phase consisted of 0.02 mol/L disodium hydrogen phosphate solution（pH adjusted to 2.4 using phosphoric acid）-acetonitrile （65 ∶ 35，V/V） at the flow rate of 1.0 mL/min. The detection wavelength was set at 237 nm，and column temperature was 30 ℃. The sample size was 20 μL. RESULTS： The linear range of dihydroartemisinin were 7.802-117.03 μg/mL（r＝0.999 9）. The limit of quantitation was 2.0 ng， and the limit of detection was 0.6 ng. RSDs of precision and reproducibility tests were all lower than 1.0％. The recoveries were 99.18％-100.46％ （RSD＝0.45％，n＝9）. Average dissolutions of dihydroartemisinin in 3 batches of samples were 94.9％， 77.9％， 89.6％， respectively. CONCLUSIONS： Improved method enhance the accuracy for the limit of sensitivity， dissolution and detection results.