The invention discloses a recovery method for extracting gallium from aluminum oxide coarse-fine liquid by using acid-process fly ashes. The method comprises the following steps: a separating step, namely carrying out ion adsorption on aluminum oxide coarse-fine liquid which is extracted by an acid process through CL-TBP extraction resin to obtain primary adsorption extraction resin and eluting the primary adsorption extraction resin to obtain a solution containing gallium; a purifying step, adding a first alkaline solution to the solution containing gallium to obtain a sediment containing gallium; a recovering step, namely recovering metal gallium from the sediment containing gallium. Gallium ions are separated from aluminum ions in the coarse-fine liquid by utilizing selective adsorption of the CL-TBP extraction resin, and the gallium ions form gallium hydroxide sediment by using the first alkaline solution. Therefore, the purity and the recovery rate of the metal gallium obtained in the recovering step can be ensured and meanwhile, the method is simple to operate and low in recovery cost.