Abstract: Two alkaloids from the aerial parts of Anisodus tanguticus were isolated by elution through series of gel columns. The alkaloid chemical structures were determined by MS and NMR and the alkaloids were identified as hyoscyamine and scopolamine . Contact toxicities of the two alkaloids on nine species of aphids including Brevicoryne brassicae and Myzus persicae, and four species of mites including Tetranychus cinnabarinus and T. urticae were measured by topical application and slide dip methods. The results showed that hyoscyamine had higher contact toxicity than scopolamine on Rhopalosiphum padi, Hyalopterus arundimis, Aphis craccivora and A. citricola with LC₅₀ values of 257.863 , 275.459, 344.645 and 344.717 mg/L, respectively. However, scopolamine was more effective in controlling A. craccivora and R. padi with LC₅₀ values of 311.585 and 392.309 mg/L, respectively. The control pesticide rotenone was most toxic to B. brassicae and Aphis gossypii with LC₅₀ values of 399.542 and 436.124 mg/L, respectively. Contact toxicities of hyoscyamine on the nine species of aphids including B. brassicae were higher than or similar to scopolamine. Compared to rotenone, hyoscyamine and scopolamine were more effective against A. craccivora and R. padi. However, rotenone was more effective against B. brassicae, M. persicae and A. gossypii. For the four species of mites tested (T. truncates, T. viennensis, T. urticae and T. cinnabarinus), hyoscyamine and scopolamine had similar effects, which included higher contact toxicities on T. urticae and T. cinnabarinus (LC₅₀: 201.027-224.172 mg/L) than on T. truncates and T. viennensis (LC₅₀: 257.014-332.698 mg/L). Rotenone was more effective than the two alkaloids against T. truncates and T. viennensis with LC₅₀ values of 196.847 and 224.592 mg/L, respectively.