Resistive switching(RS)is an interesting phenomenon which has been intensely researched during the past few decades for its potential application of non-volatile memory.This phenomenon has been discovered in many different materials and devices,and most of them are oxides.To explore the mechanism of RS effect,the Au/CoOx/Pt structure device was fabricated,which shows resistance switching effect,and its magnetic properties in different resistance states were investigated.By comparing the magnetic properties of Au/CoOx/Pt with low and high resistance states,we could investigate the mechanism of the resistive switching.The results of our work showed that the antiferromagnetic CoO/Co3O4 film could exhibit ferromagnetic properties and the saturation magnetization of low resistance state(LRS)is a little higher than that of high resistance state(HRS).This can be explained by the formation of Co filaments in the Co-oxide matrix,which is ferromagnetic and have a better conductivity,produced by a redox reaction in the film resulting from the application of electric field.Because LRS has more Co filaments than HRS,it has lower resistance and higher saturation magnetization in comparison to the HRS.By making the use of this effect,tuning the magnetic property of meltal/oxide/meltal structure in some degree by applying a bias voltage can be achieved.Furthermore,it can be a new method to prepare magnetic metal nanowires.The diameter and the length of nanowires can be modulated by the magnitude of the applying voltages and the applying time.