Twelve quinolizidine alkaloids were isolated from Sophora tonkinensis by means of silica gel, preparative MPLC, and preparative HPLC. On analysis of NMR spectroscopic data, their structures were established as 3-(4-hydroxyphenyl)-4-(3-methoxy-4-hydroxyphenyl)-3, 4-dehydroquinolizidine (1), lanatine A (2), cermizines C (3), senepodines G (4), senepodines H (5), jussiaeiines A (6), jussiaeiines B (7),(+)-5α-hydroxyoxysophocarpine (8),(-)-12β-hydroxyoxysophocarpine (9),(-)-clathrotropine (10),(-)-cytisine (11), and (-)-N-methylcytisine (12), respectively. Compounds 1-7 were first isolated from Sophora L. plant. In the in vitro assays, the isolated compounds 1, 3, 6-10 exhibited potent activity against CVB3 with IC₅₀ of 6.40, 3.25, 4.66, 3.21, 0.12, 0.23 and 1.60, and with selective index values (SI= TC₅₀/IC₅₀) of 12.0, 5.6, 13.0, 15.1, 50.1, 26.2, and 23.6, respectively. Compounds 1, 3, and 7 exhibited activity against staphylococcus aureus (ATCC 29213) with MICvalues of 8.0, 3.5, 6.0 g• L⁻ ¹, respectively. Compounds 1, 3, 7, and 12 exhibited activity against staphylococcus aureus (ATCC 33591) with MIC values of 18.0, 7.5, 8.0, 12.0 g• L⁻ ¹, respectively. Compounds 2, 6, 7 exhibited activity against Escherichia coli (ATCC 25922) with MIC values of 1.0, 3.2, 0.8 g• L⁻ ¹.