The physics mechanisms of radiation belt electrons loss and acceleration are important issues in space physics research. Recently, France Microsatellite DEMETER has discovered the correlation between man-made VLF signals and radiation belt electrons precipitation in the NPM(the U.S. VLF transmitter located at Lualualei) experiment. Our research focuses on the explanation of the relation among affected pitch angle distribution, kinetic energy and position of electrons. This is achieved by calculating the local diffusion coeffcient based on the theory of qusi-linear diffusion with resonant interaction. Our result has a good explanation of radiation belt electron precipitation discovered by DEMETER during NPM experiment. Furthermore, we have discussed the effciency of radiation belt remediation in an artificial way.