Abstract: A measurement method for magnetic properties of grain-oriented（GO） silicon steel sheets powered by pulse width modulation（PWM） power supply is proposed.singlesheet tester（SST） is used to measure the magnetic properties of silicon steel sheets under PWM power supply by controlling magnetic flux density of the fundamental and the harmonic waves at the same time.A dynamic hysteresis model taking account of the eddy current in the silicon steel sheets is presented.The effects of high order harmonics,the local minor loop induced by the pulse voltage,magnetization history and the eddy current induced by high order harmonic are considered.The coercive force,reluctivity coefficients and dynamic parameters are obtained from experimental B-H curves which can predict the dynamic hysteresis accurately.The proposed calculating method can model the complex magnetic character of silicon steel sheets under PWM power supply,and calculate the specific loss accurately by comparing calculation and experiment results.