The invention provides a method for extracting gallium from fly ash based on a resin method. The crude semen obtained after acid leaching of fly ash is used as a raw material. Gathering gallium, neutralizing and removing iron, transformation and precipitation of gallium, liquid making and purification, electrolytic deposition and other steps, thus realizing the extraction of gallium from fly ash. Compared with the existing technology, the method of the present invention is based on the resin method, the amount of reagents such as lye is significantly reduced, and there is no need to use additional reagents such as iron masking agent and reducing agent, avoiding the generation of a large amount of waste water, economical and environmentally friendly, and the extraction efficiency of gallium has also been greatly improved. The method of the invention has stable process, reliable operation and controllable cost, and is a novel gallium extraction process with very promising application prospects.