Abstract: Radix Peucedani(Qianhu)，the root of Peucedanum praeruptorum Dunn or Peucedanum decursivum (Miq.) Maximo (Umbelliferae)，possesses the efficacy of dispelling wind-heat，relieving cough and reducing sputum.It has been used for the treatment of colds and headaches，cough，dyspneal fullness and tightness in the chest，etc.Both the Traditional Chinese Medicine (TCM) theory and the clinical practice have proved that Radix Peucedani is an important Chinese medicines for curing respiratory diseases.In the light of the importance and research status of Qianhu，this project focused on the chemical constituents of Qianhu，guided by the pharmacological efficacy of its clinical relevance.A series of systematic studies have been carried out，which including the extraction and separation，structural elucidation，enantiomer separation，structural modification and total synthesis of bioactive constituents of Qianhu.Based on these systematic studies，further studies were foucus on the rationality evaluation of the use of its substitutes，scientifically design of its quality control standards，the separation and structural elucidation of its characteristic constituents，etc.The main goal is to clarify the material basis of the clinical efficacy of Qianhu and propose a scientific quality control standard for the development of the new drugs with Chinese characteristics and independent intellectual property rights.