The invention provides a magnetic field screening machine with high-efficiency ore feeding performance. The magnetic field screening machine comprises an ore feeding barrel, an ore separator, a screen sheet, a box body, an ore feeding unit and an ore discharge unit, wherein the ore feeding unit comprises a plate-shaped main body, an ore separation groove, a slurry groove, a water supplement pipe and a control valve; the ore separation groove is formed in the plate-shaped main body; the slurry groove is formed in the edge of the plate-shaped main body; the water supplement pipe is mounted at the outer side of the edge of the plate-shaped main body and comprises a plurality of water spray nozzles; the control valve is arranged on the water supplement pipe. According to the magnetic field screening machine, the ore feeding unit is innovated and improved, so that when deposit ore exists on the ore feeding unit, the control valve on a water supplement pipeline is opened, and the deposit ore on the ore feeding unit can be washed away timely by high-pressure water flow, so the work efficiencies of the ore feeding unit and the magnetic field screening machine are improved, and the service lives of the ore feeding unit and the magnetic field screening machine are prolonged.