The insecticidal protein produced by Pseudomonas pseudoalcali genes is purified f rom the sus-pension of the bacterial culture. As an intact molecule, the protein act s on the foregut, midgut, hindgut, vasa Malpighii and fat body, and kills locust s. The disinsection rates of feeding and in-jection are 63.3% and 65.7%, respectively. After 24h to 48h, it is observed that all these tissues and cells show pathological changes in varying degrees, and so did the host cellular organs of these cells, such as cytoblast, mitochondria, endoplasmic reticulum and ribosome. Particularly, the changes of the mitochondria are much more serious than those of others. Detection of oxygen elec-t rode shows the efficiency of oxidative phosphorylation and the ATP synthesis decreases, while the activity of mitochondrial ATPase is almost not affected. That means the energy utilization of locust s is in gear, but the shortage of the supplying of energy result s in their death. This research forms the substantial basis for cont rolling locusts.