The invention discloses a process method for producing metal aluminium by high-alumina fly ash, which comprises the following process steps: firstly, dissolving fly ash out, that is, mixing high-alumina fly ash containing not less than 38% of Al2O3 with hydrochloric acid with a concentration of 20-30% to prepare raw pulp, dissolving out alumina in the fly ash at a high temperature through a continuous dissolving mode of heat insulation dissolution by a preheater and an autoclave; secondly, separating and washing acid sludge, and purifying an aluminium chloride solution for impurity removal; thirdly, performing spray drying and dehydration to obtain anhydrous aluminium chloride crystal particles; fourthly, electrolyzing the molten salts, that is, adding the anhydrous aluminium chloride into an aluminium chloride electrolytic tank, dissolving the anhydrous aluminium chloride in a molten electrolyte, wherein the temperature in the electrolytic tank is 670-700 DEG C, performing electrolyzation to obtain aluminium liquid, delivering the aluminium liquid to a casting procedure, performing purification and clarification, then preparing aluminum ingots, delivering the chlorine generated at an anode of the electrolytic tank to a hydrochloric acid preparation procedure; fifthly, preparing hydrochloric acid. The process of the invention obtains aluminum ingots by treating high-alumina fly ash, which make reasonable use of fly ash.