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In order to explore the principle of metal composite assisted by high frequency pluse current, the test of rolling-welding magnesium composite plates prefabricated notch assisted by high frequency pulse current is designed.The microstructure evolution and mechanical properties of bonding interface and areas near interface of the composite plates were compared under different loading frequencies (25 kHz, 50 kHz, 75 kHz).The morphological characteristics of microstructures near interface of magnesium alloy composite plates was observed by metallographic microscope;Nanoindentation test and Vickers hardness test were used to characterize the characteristic of the interface micro-region and cross section hardness distribution respectively;The tensile properties and fracture morphology of magnesium alloy composite plates were analyzed by tensile testing machine and electron microscope.The results show that with the increase of the frequency, the composite effect of the interface increases first and then decreases;when the high frequency current parameter is 50 kHz, the tensile strength and elongation of magnesium alloy composite plates are the best, reaching 292.52 MPa and 25.7%, respectively.This can be contributed to the comprehensive role of skin effect、proximity effect、Joule heat effect of current and contact resistance of interface micro-region.