Abstract: The biological activity of Dodonaea viscosa saponin to Pieris brassicae was determined by leaf dipping method. The results showed that the growth inhibition rates of 500, 1 625, 2 750, 3 875 and 5 000 μg/mL D.viscosa saponin treatments on the 4th instar larvae of P.brassicae were 14.47%, 31.54%, 49.70%, 62.48% and 79.94% respectively, at 24 h, and were 2.72%, 39.26%, 54.82%, 70.53% and 86.39% respectively, at 48 h. D.viscosa saponin had significantly antifeedant activity on the 4th instar larvae of P.brassicae, and the antifeedant rates of the 5 treatments of D.viscosa saponin mentioned above were 30.21%, 40.62%, 54.33%, 72.47% and 84.84% respectively, at 24 h, and were 4.4%-86.67% at 48 h. The P.brassicae larvae pupate rate of 5 000 μg/mL treatment was 32% after 14 d, which was significantly lower than that of the control (72%). And the P.brassicae emergence rate of the 5 treatments of D.viscosa saponin mentioned above were 56%, 44%, 44%, 36% and 32% respectively, after 23 d, which was lower than that of the control (64%). The results showed that D.viscosa saponin had significant inhibitory activity on growth, development, feeding and pupation of P.brassicae.