The invention discloses a magnetic positioning device for milling the heel of a switch rail and relates to the field of positioning equipment. The magnetic positioning device for milling the heel of the switch rail comprises a supporting platform and a conveying mechanism, a lifting device and a magnetic attraction device, wherein the conveying mechanism, the lifting device and the magnetic attraction device are located on the supporting platform; the conveying mechanism comprises sliding rails located at the left end and the right end of the attraction device correspondingly; the lifting device is composed of bearing plates, baffles which are arranged on the bearing plates and are perpendicular to the bearing plates, and rollers located at the lower ends of the bearing plates; the magnetic attraction device comprises an attraction table and magnetic assemblies arranged in the attraction table; each magnetic assembly comprises an iron core and a coil wound around the iron core, the coil is electrically connected with a control cabinet on the supporting platform through a wire, and the attraction face of the vertical attraction table is a protruding C-shaped face; and the supporting platform is provided with a taking-up and paying-off device which comprises a three-phase asynchronous motor, a paying-off rack, a first guide pulley and a second guide pulley. According to the magnetic positioning device for milling the heel of the switch rail, by performing horizontal and vertical positioning on a switch rail body, positioning is more stable and firm, the heel of the switch rail can be machined conveniently, and the machining efficiency is improved.