The invention discloses a method for coating a nylon resin spline. The method comprises the steps of cleaning, drying, sand blasting, heating, primer dipping, oven drying, high-frequency heating, resin coating, cooling, spline cutting and hot running-in, and specifically comprises the steps that surface cleaning is carried out on a spline shaft needing coating, and the spline shaft is placed into a drying bin to be dried after being cleaned; sand blasting is carried out through a sand-blasting machine; the spline shaft is moved to a heating bin to be heated; the spline shaft is dipped into a primer tank, and then is placed into the drying bin to be dried in a baking mode; the spline shaft is heated through a high-frequency heating machine; after the spline shaft is heated, the spline shaft is moved to a coating tank to be coated, and then is placed into a cooling tank to be cooled; after cooling is accomplished, a spline cutting machine is used for cutting the spline shaft, and finally the cut spline shaft is moved to a running-in platform to carry out running-in. According to the nylon resin spline, the technology that hot running-in is carried out after coating and cutting are accomplished is adopted, the sliding spline has high abrasive resistance, high and low temperature resistance and corrosion resistance, and has small sliding force and a small running clearance, reliability of a product is greatly improved, and the service life of the product is greatly prolonged.