Abstract: To study the effects of Cry1Ab protein on ecology security of non-target organisms, enzyme-linked immunosorbent assay (ELISA) was applied to test Cry1Ab protein of Drosophila melanogaster and ultraviolet spectroscopy was applied to test the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and acetylcholinesterase (AChE) in Drosophila melanogaster. The results showed that Cry1Ab protein continuously accumulated in the first 10 days. Compared with the normal level, specific activity of AChE, SOD and GSH-Px were inhabited. The inhibition on the activity of AChE was strengthened, and the activities of GSH-Px and SOD were reduced with the increasing content of Cry1Ab protein. After 10 days, content of poisonous protein was reduced, inhibitions on AChE, SOD and GSH-Px were reduced, but activities of the three enzymes were still lower than those of the control groups. These results suggest that there is bio- concentration of Cry1Ab protein and specific activity of AChE, SOD, GSH-Px can be inhabited.