Nine new isoquinoline alkaloids, including two proaporphine (1–2), three aporphine (3–5), two oxoaporphine(6–7), and two seco-bisbenzylisoquinoline (8–9), together with three known alkaloids (10−12) were isolatedfrom the whole plant of Thalictrum wangii. Their structures were established on the basis of spectroscopic data.The antitumor activities of the isolated compounds were evaluated in vitro against glioma stem cells. Compounds3–8 showed the cytotoxicity with IC 50 values 15–20 μg/mL.