The invention discloses a method and breeding sewage treatment system for treating breeding sewage through pulverized fuel ash. The breeding sewage treatment system for treating the breeding sewage through the pulverized fuel ash comprises a feces collection pond, a solid-liquid separation device, a slurrying tank, an adsorption treatment device, a sterilization device and a sludge collection pond. The adsorption treatment device comprises a first treatment tank, a second treatment tank, a third treatment tank, a fourth treatment tank and a fifth treatment tank which are connected in sequence.The breeding sewage enters the adsorption treatment device to be subjected to adsorption treatment with pulverized fuel ash slurry, pores inside the pulverized fuel ash are rich, the specific area islarge, the capability of adsorbing and flocculating pollutants is high, decoloration and deodorization can be effectively achieved, and organic matter, heavy metal ions, bacteria and other microorganisms, suspending colloid impurities and the like in water are removed; water is purified, secondary utilization of solid waste is achieved, the sewage treatment cost is lowered, after the breeding sewage is subjected to five stages of adsorption treatment, the COD value and chromaticity in the sewage can be effectively lowered, the effluent can be recycled, and the use quantity of water resourcesis reduced.