Abstract:Six alkaloids were isolated from Radix Sophorae Tonkinensis. On the basis of spectrometric analysis and physico-chemical constants they were identified as (Ⅰ) (+)-matrine, (Ⅱ) (-)-cytisine, (Ⅲ) (+)-matrine N-oxide, (Ⅳ)(+)-sophocarpine N-oxide, (Ⅴ)(+)-sophoramine and (Ⅵ) (+)-sophoranol respectively. (Ⅱ), (Ⅳ), (Ⅴ) and (Ⅵ) were isolated for the first time from Radix Sophorae Tonkinensis.