Abstract: Magnetic switch is the key part of magnetic pulse compression system. The performance parameters of magnetic switch core directly affect the overall performance of the magnetic pulse compression system. According to the physical properties and application features of the ferrite core, a loop oscillation circuit is designed to test the dynamic characteristics of the magnetic cores under fast pulse excitations, and the hysteresis loops of the ferrite cores under hundreds of nanoseconds excitations are obtained. The diagnosis of the winding current and the change rate of magnetic flux on the magnetic core provides necessary value for determining the hysteresis loop, saturated magnetic flux intensity and coercivity of magnetic core. A magnetic pulse compression circuit model with dynamic hysteresis loop is established based on the experimental measurement parameters, and the effect of the dynamic characteristics of the magnetic switch on the voltage transfer is studied.