Radix Sophorae Flavescentis is a traditional Chinese medicine, which is the roots of Sophora flavescens and is used to treat abscess, dysentery, eczema and skin itch. The main active compounds of the roots of Sophora flavescens are alkaloids and flavonoids. To provide reference compounds for HPLC-DAD qualitification analysis of flavanonoids and for study on the bioactivities of flavanonoids, six main flavanonoids were isolated from the roots of Sophora flavescens. They are 5-methoxy-7, 2', 4'-trihydroxy-8-[3,3-dimethylallyl] -flavanone (1), isoxanthohumol (2), 3/beta, 7, 4'-trihydroxy-5-methoxy-8-[3,3-dimethylallyl] -flavanone (3), nor-kurarinone [(2S) -sophoraflavanone G] (4), kurarinone (5) and kushenol I (6). Compound 1 is a new compound, and compound 3 is obtained from Sophora flavecens for the first time. The 13C NMR data of compounds 3 and 5 are reported for the first time.