The invention relates to the technical field of steel piece surface treatment, and in particular relates to a preparation method of a high-temperature wear-resistant
coating on the surface of a steel piece. According to the preparation method, a
composite coating of a Fe-Al
intermetallic compound and a little Al2O3 is obtained through liquid dip aluminum plating and subsequent compound dispersion treatment. The process flow of the preparation method comprises pretreatment (alkali cleaning, acid
pickling and assisted plating), dip aluminum plating and dispersion treatment, wherein the dip aluminum plating is carried out for 1-10 minutes in liquid aluminum at a temperature
ranging from 720 DEG C to 800 DEG C; and compound dispersion annealing which is carried out in a protective
atmosphere or in vacuum at a temperature
ranging from 850 DEG C to 1100 DEG C for 1-5 hours, and in air at a temperature
ranging from 400 DEG C to 600 DEG C for 20-30 minutes. The temperature and the time of the dispersion treatment are adjusted so that composite wear-resistant coatings containing the
intermetallic compound and a little Al2O3 and are different in thickness can be obtained. The preparation method has the characteristics of simple and convenient process, low cost, high
coating binding force, excellent high-temperature
wear resistance and the like, and thus can be widely applied to surface strengthening of high-temperature wear resisting steel pieces.