The invention discloses a curing method for heavy metals in waste incineration ash and application thereof. The curing method comprises the steps of (1) mixing waste incineration ash with water to form a mixture according to a certain proportion, putting the mixture in a ball milling pot, and then, adding grinding balls into the ball milling pot; and (2) sealing the ball milling pot, then, enabling the ball milling pot to perform ball milling treatment under the driving of a planetary ball mill, then, opening the ball milling pot, separating the grinding balls to obtain a ball milling product, then, filtering the ball milling product, and drying filter residues for 4 h to 24 h at the temperature of 60 DEG C to 85 DEG C, so as to obtain waste incineration ash with cured heavy metals. According to the curing method, key ball milling technologies such as the proportion of the mixture, the mass and diameter specifications of the grinding balls and the reaction conditions of the follow-up treatment technologies are improved, the harmful heavy metals in original waste incineration ash are cured, the leaching is reduced, and the environmental protection application approach of waste incineration ash is expanded.