Abstract: After the antiucancer drugs Oxyavicine and pyrrolizidine alkaloids acted on the A₅₄₉ lung cancer cells. We observed the growth curve, mitotic index and ulrastructure changes, contrast with control cells, the result indicated that after the drugs affected, the slope of the growth carve descended, the maximum density reduced and the mitotic index decreased. and there existed some evideat uitrastructure changer under transmission electron microscope and scan electron-microsope the result suggest that both drugs can restrain the growth of A₅₄₉ lung Cancer cells, damage the ultrastructure of cancer cells, and they hvae synergy as they were jointlyused.