A high silicon steel plate having an excellent magnetic property and a manufacturing method thereof are provided. According to the present invention, the method for manufacturing a high silicon steel plate comprises: a strip casting step for performing strip casting on a molten silicon steel under a nitrogen or argon atmosphere, the molten silicon steel consisting of 4 to 7 wt% of Si, 0.1 to 3 wt% of Al, and 5.5 to 7.5 wt% of the sum of Si and Al, the remainder being Fe; a hot rolling step for performing hot rolling on the strip-cast strip to manufacture a high silicon steel plate; a heat treatment step for performing heat treatment on the hot-rolled high silicon steel plate in a non-oxidizing mixed atmosphere of nitrogen and argon or hydrogen and nitrogen; a warm rolling step for performing warm rolling on the heat-treated high silicon steel plate to a final thickness of 0.5 mm or less; and a final heat treatment step for performing final heat treatment on the high silicon steel plate at a temperature of 800 DEG C to 1200 DEG C, wherein the method further comprises the step for forming a soft ferrite layer on the surface of the high silicon steel plate, which is manufactured to the final thickness, in order to improve a magnetic property in a high frequency region after performing the final heat treatment step.