Abstract: Among the various technologies of safety inspection,CT technique has become one of effective technologies.The first generation X-ray CT has high radio of wrong alarm and missing alarm.The new development has solved this problem.Comparing with X-ray security inspector,CT's security inspector have many advantages,because it is fundamental improvement.The fundamental improvement is three-dimensional imaging and determining density and the atomic number,overcoming the problem-double image of the X-ray security inspector.This techology can accomplish comparing physical characteristics with dangerous materials automaticly,reducing influence from human beings.The result is to lighten labor intensity of secruity staffs,also to guarantee the effect of security check.With the terrorism creeping all round the world,there is a large market for CT's security inspector.