Tubers of Corydalis turtschaninovii were extracted with 80% aqueous methanol (MeOH), and the concentrated extract was successively partitioned with n-hexane, ethyl acetate (EtOAc), butanol (n-BuOH), and $H_2O$. An activity-guided fractionation to search for insecticidal compounds against aphids led to the isolation of six alkaloids from the n-hexane and EtOAc fractions using a repeated silica gel, an octadecyl silica gel (ODS), and Sephadex LH-20 column chromatographic separations. Based on the spectroscopic data of NMR, mass spectroscopy (MS), and IR, the chemical structures of the compounds were determined to be: (+)-stylopine (1), (+)-corydaline (2), demethylcorydalmine (3), isocorypalmine (4), glaucine (5), and pseudoprotopine (6). These compounds showed significant insecticidal effects against Aphis gossypii, $69.7{pm}7.2$, $46.9{pm}2.4$, $68.5{pm}8.6$, $75.5{pm}4.2$, $80.2{pm}9.7$, and $78.9{pm}11.3%$ at 1,000 ppm, respectively.