The invention discloses a platinum-cobalt permanent magnetic multi-pole ring and a preparation method thereof, belonging to the technical field of permanent magnetic multi-pole rings. The platinum-cobalt permanent magnetic multi-pole ring comprises the following chemical components in mass percent: 73-81% of Pt and the balance of Co; and the Pt and the Co with purities above 99.99% are placed in an induction furnace for smelting and then poured in a cooling cover die after the smelting, wherein the cooling cover die has even temperature gradient along the direction of the diameter so that a platinum-cobalt alloy cast ingot forms an radial crystal structure. The preparation process comprises the steps of: smelting the platinum-cobalt alloy by using a vacuum induction furnace and forming a radial crystal structure in a pouring cover die; carrying out solid solution heat treatment; carrying out secondary ageing heat treatment by using a salt bath heat treatment manner; and machining intoa ring-shaped magnet. The invention has the advantage of realizing the platinum-cobalt permanent magnetic radial multi-pole ring which is simple in preparation process and good in uniformity of air-gap magnetic field along circumferential direction.