The invention discloses core iron for a magnetic device. The core iron comprises a shaft, an amorphous alloy body which is formed by winding iron-based amorphous alloy strips on the shaft through annealing treatment and an encapsulation layer which is used for encapsulating the iron-based amorphous alloy to enable the iron-based amorphous alloy to be isolated from the external environment. The core iron not only has the excellent magnetic property but also can effectively avoid the problems that the dreg dropping and breaking phenomena occur when the amorphous alloy is frictionally collided due to the fact that the amorphous alloy is directly exposed to the surface, and the stress sensitivity is high and the corrosion resistance is poor due to the fact that the amorphous alloy directly makes contact with the external environment and other structural units. In addition, by preferably adopting a manufacturing method of winding the iron-based amorphous alloy strips with the different widths, the problems that amorphous alloy structure machining is high in difficulty and low in precision are solved, and a good application prospect is achieved in devices such as electromagnets and electromagnetic valves.