The invention provides a core, which comprises a core body, wherein an accommodating groove is formed in the surface of the core body in a penetrating manner; a rigid frame is accommodated into the accommodating groove of the core body; the core body is made of an amorphous alloy material; and the rigid frame is made of a silicon steel sheet. The invention further provides a transformer of adopting the core, wherein the transformer also comprises a winding wound on the core; and the rigid frame is located between the winding and the core body. According to the transformer, the rigid frame is circularly arranged on the inner wall of the amorphous core body, so that the winding is provided with enough radial clamping force, and also provided with strong support, deformation and destabilization of the winding can be prevented, and the damage caused by mutual extrusion of the winding and the amorphous core body under the action of short-circuit force when the transformer in a short circuitcan be avoided.