Abstract: The velocity effect of MFL inspection under high speed induces the distortion in the detection signal. According to the basic principle of velocity effect on MFL inspection, it showed that eddy current induced by velocity is one of the factors which influence the MFL signal directly and the size of eddy current is proportional to velocity and magnetic field intensity. In this paper, a new model of high speed inspection was produced based on this characteristic. Different finite element analysis were used for the defective rail module. Detection signals of this module were compared with the signal from the classical magnetic leakage module. The effect of the eddy current was deeply studied.