The invention discloses a deep hydrolysis method of aluminum nitride in aluminum ash. The deep hydrolysis method comprises the following steps of 1) crushing the aluminum ash to form aluminum ash withthe particle size being 10mm or below, then heating the aluminum ash to a certain temperature, and uniformly mixing the heated aluminum ash and water according to a certain ratio; 2) performing grinding and hydrolyzing on obtained high-temperature slurry, and collecting ammonia gas produced by hydrolyzing at the same time to obtain corresponding ammonia water or ammonium salt; and 3) performing dewatering and filtering on the slurry after hydrolyzing to obtain a filter cake and a filtrate, and performing evaporation to recover industrial salt after circulating enrichment of the filtrate. According to the deep hydrolysis method provided by the invention, through the hydrolysis process of high temperature grinding and strengthening the aluminum nitride, deep hydrolysis of the aluminum nitride is realized, ammonia recovery is realized at the same time, so that a new way of harmless and resource utilization of the aluminum nitride in the aluminum ash is opened up.