The invention discloses an absorbent for refining and de-coloring waste transformer oil, which is prepared by mixing silver nitrate, copper sulfate and aluminum chloride according to a mass part ratio of 0.1: 1: 100, adding water for soaking the mixed material, completely blending the mixed solution and drying the mixture in an oven for use. In the invention, the silver nitrate, copper sulfate and aluminum chloride are used as the absorbent of a reduction refining system, and a natural precipitation method is adopted to quickly and efficiently remove harmful components in the waste transformer oil and perform de-coloring, so that all indexes can reach or approximate the criteria of new oil. The absorbent has the advantages that: the used amount is small, discharge is small, environmental pollution can be reduced, and the environment and the body health of workers can be protected.