The invention relates to a preparation method of nitrile butadiene rubber for preparing a seal ring of a floating oil seal with high wear resistance. The preparation method comprises a formula and a preparation process, wherein the formula comprises the following components: nitrile butadiene rubber, N-550 carbon black, high-wear resistant carbon black, semi-reinforced carbon black, calcium carbonate, polyvinyl chloride, stearic acid, dibutyl ester, sulfur, accelerant, accelerant TE, accelerant TMTD, anti-aging agent RD, anti-aging agent 4010 and zinc oxide; the preparation process comprises the following steps: adjusting the temperature of a mixing machine to 100 DEG C, keeping the rotational speed at 32 revolutions/min, putting rubber raw material, a filling agent, a softening agent, an acidifying agent, the anti-aging agents and an activator into the mixing machine to mix for 20min, controlling the rubber temperature below 130 DEG C to discharge the rubber, then transferring to an open mill, and cooling extruded sheets to obtain a master batch; and putting the master batch into the mixing machine, adding a vulcanizing agent, blending, mixing, controlling the rubber temperature below 100 DEG C to discharge the rubber to the open mill, then cooling the extruded sheets, standing and curing to obtain the nitrile butadiene rubber for preparing the seal ring of the floating oil seal with high wear resistance.