Abstract: The ultrastructural changes of the germinal membrane of Echinococcus granulosus treated with total alkaloids isolated from Corydalis stricta Steph for 60 days were observed. Cysts from the total alkaloid-treated mice were shown by transmission electron microscopy to have dissolution of the microtriches, disturbance of organelles in their arrangement, disrupted aggregates of microtubules, increase in size and number of lysosomes, decrease in number of normal appearing Golgi bodies, decreased density and swelling of mitochondria. Many pits were observed arising from the outer and interior surface of the germinal membrane as the outer surface of ulcer under scanning electron microscopy. It scems clear that the total alkaloid has a profound intracellular effect on experimental Echinoeoccus granulosus cysts in mice. Changes of the structure and its function caused by the total alkaloids were also discussed.