Bt toxin Cry1Ac could be introduced into soil by pollen, root exudates, and plant residues. To investigate its toxic effects, the Bt toxin was added into an earthworm-cultured artificial soil, and the survival, growth rate, sperm count, protein content, and activities of acetylcholinesterase (AchE), catalase (CAT), glutathione S-transferase (GST) and cellulase in Eisenia fetida were determined. The results suggested that Bt toxin Cry1Ac had little effects on the biomass and physiological characteristics of E. fetida, with no acute and subchronic toxicity, and was safe for earthworm at field dose level.