The invention provides a treating agent for treating pigs died from diseases, a preparation method and a treating method for the pigs died from diseases, and relates to the technical field of treatment for animals died from diseases. The treating agent mainly comprises raw materials such as bacillus subtilis, saccharomycetes, alkaline protease, keratinase, lipase, aspergillus niger, actinomycetesand bacillus licheniformis. The treating agent has good decomposition processing capacity for the pigs died from diseases and can completely degrade dead pig carcasses by utilizing the organic matterdegrading capacity of microorganisms, combing the synergistic characteristic between specific biological strains, and scientifically and reasonably matching the raw materials of the strains, thereby realizing innocent treatment of the dead pig carcasses; in addition, the dead pig carcasses treated by the treating agent can be finally converted into high-quality organic fertilizer raw materials, thereby turning waste into wealth and realizing resource reutilization. The invention further provides the treating method for the pigs died from diseases, and improves the defects that the treating method in the prior art is long in treating time, large in occupied area, harmful in treatment, and high in stealing possibility.