The invention discloses 1120 alloy aluminum foil of a flexible sticky ceramic welding backing and a processing technology thereof. According to the 1120 alloy aluminum foil, copper, iron, silicon and aluminum are adopted as main raw materials, the copper, the iron and the silicon are proportioned according to the weight ratio being 2 to 1 to 0.5, and the aluminum foil is obtained through the technological steps of smelting, continuous casting-rolling, cold rolling, recoiling and trimming, intermediate annealing, foil rolling, aluminum foil surface roughening, aluminum foil surface cleaning, aluminum foil shearing and splitting and finished product annealing. The produced 1120 alloy aluminum foil of the flexible sticky ceramic welding backing is 0.05-0.07 mm thick and has excellent flexibility, adhesiveness, heat resistance and thermal conductivity. Aluminum foil tape produced through the aluminum foil is good in flexibility, the part, adhering to the bottom of base metal in the heat-affected zone surrounding a welding line, of the aluminum foil tape is high in adhesiveness and good in heat dissipation effect and does not get deformed and warped or fall off easily on the condition of welding arc heating effect, and the use requirement of keeping stable in the welding process of the ceramic welding backing can be met.