Abstract: The Fe5 alloy was overlaid on low carbon steel by plasma arc surfacing with longitudinal magnetic field.The style of magnetic field was changed during surfacing,which was direct magnetic field or alternating magnetic field.After plasma arc surfacing with magnetic field,the scanning electron microscopes,wear loss test,micro-hardness test were used to analyze the effect of magnetic field style on the properties of overlay deposit.The acting mechanism of magnetic field style and parameters on the properties and microstructure of the deposit was researched.The results indicate that the introduced DC/AC magnetic field can give an effective intervention to the properties of the deposit.The active effect of AC magnetic field is better than that of DC magnetic field because the magnetic field can be controlled during AC magnetic field by alternation of magnetic field frequency.The optimal result is acquired when magnetic current is 3 A and magnetic frequency is 10 Hz,and the hardness of the properties is 68 HRC and wear loss is 0.031 8 g.