The invention discloses a method for freezing and thawing treatment of dewatered sludge of a domestic sewage treatment plant. The method comprises the following steps: mixing dewatered sludge with the water ratio of 80+/-2%, fly ash and coal gangues in a volume ratio of (2.5-4):(1-2):(5-7), and then stacking the mixture on the ground with the thickness of 30+/-5cm; and freezing the compound mixture by using a temperature lower than the freezing point at night in winter, wherein when the temperature rises before planting in spring, the frozen compound mixture is thawed. The single freezing and thawing treatment of the dewatered sludge of the domestic sewage treatment plant can ensure that the treated sludge is compact, poor in air permeability and high in salt content and can influence seedling emergence, but according to the method disclosed by the invention, the freezing and thawing treatment is ingeniously performed by mixing the sludge with the fly ash and the coal gangues, so that the problems are solved. Meanwhile, the natural condition of the winter is utilized to solve the problems of odor pollution and pathogenic bacteria pollution of the sludge. Moreover, by using the method disclosed by the invention, the problem that heavy metals in the sludge influence plants is solved.