The invention discloses a vertical-ring high-gradient magnetic separator which comprises a cooling system and a mineral flushing system; the cooling system comprises a magnet exciting coil, an oil pump and a cooler; the mineral flushing system comprises a filter and a mineral flushing water pipe; the mineral flushing water pipe comprises a positive mineral flushing water pipe located on the outer side of the upper part of a revolving ring, and a negative mineral flushing water pipe located on the inner side of the upper part of the revolving ring; the magnet exciting coil comprises magnet exciting wire coils arranged in an inner cavity of a coil case; each magnet exciting wire coil is obliquely arranged in a vertically multilayer manner; the outer circumference of each magnet exciting wire coil is higher than the inner circumference of the magnet exciting wire coil; interlayer insulation filler strips are arranged among gaps of each magnet exciting wire coil in a spaced manner, and interlayer cooling liquid channels are formed; inner holes of the coil case are in waist drum shapes; and two oil inlets are formed in one end of the coil case and two oil outlets are formed in the other end of the coil case. The vertical-ring high-gradient magnetic separator is high in oil flowing speed, good in heat dissipation effect, and good in mineral flushing effect; the problem that vibration friction is generated when the magnet exciting coil is electrified is solved; the stability and the service life of the magnet exciting coil is improved and prolonged; and the requirements of the large vertical-ring high-gradient magnetic separator are met fully.