The WC/316L metal-matrix gradient coating was prepared by laser melt injection under a steady magnetic field. The influence of the steady magnetic field on the distribution of hard particles and the microstructure in the composite layer is discussed. The results show that the steady magnetic field can suppress the flow of the molten pool and reduce the drag force on particles in the molten pool. With the increase of the magnetic flux density, the volume rate of WC particles in the upper part of the LMI layer increases. The phase type is preserved no matter whether the steady magnetic field is added or not. However, the content of W-phase significantly increases. The size of the eutectic structure becomes larger and the quantity does as well.