Objective:To determine the content of piefeltarraenin IA in different medicinal parts of Picria fel-tarrae in different growth periods.Method: High performance of liquid chromatography（HPLC） was adopted

the separation was performed on C18 column with acetonitrile-0.1% aqueous acetic acid solution（36∶64） as mobile phase

the flow rate was 1 mL·min-1

the detection wavelength was set at 264 nm and the column temperature was kept at 25 ℃.Result: From the last year in June to the next year in January

average content of piefeltarraenin IA in leaves were listed monthly as follows: 0.37%

0.66%

0.59%

0.45%

0.35%

0.34%

0.31%

0.23%;and in the stems: 0.24%

0.38%

0.36%

0.24%

0.13%

0.08%

0.03%

0.02%;the content of piefeltarraenin IA in roots was 0.18% in July and was not detected in other times of the whole year.Conclusion: The content of piefeltarraenin IA was highest in July and August

regarded the content of piefeltarraenin IA as standard

the optimum collection time of Picria fel-tarrae was in July and August.This research could provide scientific basis for optimizing the collection time and actualizing standard planting of Picria fel-tarrae.