Abstract: The theory of the lifetime of a charged artificial Satellite mov-ing in the earth's gravitational and magnetic field under the atmospheric dragis studied from an energy point of view in this paper.The formula of thelifetime is derived Which is concerned with charged Satellite in circularOrbit.We conclude that the lifetime of a charged Satellite is longer thanthat of the same noncharged Satellite,the more charge it has,the longer life-time it will have.As an example,the effect of charge carried on the Sate-llite on its lifetime is estimated numerically.