Objective: To study the alkaloids constituents of Sophora tonkinensis var. polyphylla. Method: Sephadex LH-20

slica column chromatography and recrystallization were used to isolate and purify the alkaloidal constituents from S. tonkinensis var. polyphylla. Then infrared spectra(IR)

mass spectra(MS)

nuclear magnetic resonance(NMR) and other physicochemical methods were used to identify the chemical structures of the alkaloids constituents. Result: The structures of alkaloids were identified as:sophocarpine(1)

matrine(2)

5α-hydroxymatrine(3)

9α-hydroxymatrine(4)

12α-hydroxysophocarpine(5)

oxysophocarpine(6)

oxymatrine(7)

and cytisine(8)

respectively. Conclusion: All of the alkaloids were isolated from this plant for the first time.