Astragali Radix is a commonly used traditional Chinese medicine whose main active compounds include isoflavones,polysaccharides and triterpene saponins,among which astragalus polysaccharide and astragaloside Ⅳ have been developed as veterinary antiviral drugs.Due to the rising market demand for Astragali Radix and its active compounds,it is increasingly important to explore alternative ways of plant extraction.Hairy root provides a potential alternative source for production of active secondary metabolites in plant and it is an important system to study the biosynthesis pathway of plant secondary metabolites.This technique has been used in the research of A. membranaceus for a long time.In this paper,studies related to hairy root of A. membranaceus were reviewed from five aspects:establishment and optimization of hairy root system,effects of different elicitors on hairy root growth and active component content,comparison of hairy root extract with cultivated plant extract,transgenic technology to increase the content of astragaloside Ⅳ in hairy root,and studies on astragalosides biosynthetic pathways based on hairy roots.