Objective: To establishing the quality control standard and provide scientific basis for the utilization and development of Hedyotidis diffusa. Method: Twentytwo batches of H. diffusa were collected. The morphology

inspection

identification and the content of target components in these crude drugs were studied. TLC method was used to identify this crude drug. The contents of deacetyl asperulosidic acid methyl ester in these samples were determined by HPLC. Result: Macroscopic and microscopic characteristics of H. diffusa were described. According to the measurement results

moisture in the crude drug was equal or below 6%

the content of total ash was equal or below 13 %

the content of acid-insolubal ash was equal or below 5%. The extractum by hot water was above 10%. The spot of TLC were clear and well-aparated. The linear range of deacetyl asperulosidic acid methyl ester were 0.019-2.44 μg(r=1.000 0); the average recoveries were 98.28% and RSD of them were 2.73(n=6); the content of deacetyl asperulosidic acid methyl ester were above 0.1 mg·g-1. Conclusion: The quality is suitable for H. diffusa.