The invention discloses a method for preparing no-yellowing polyurethane sponge capable of being foamed at normal temperature. 4,4'-dicyclohexylmethane diisocyanate or a prepolymer thereof and polyether polyol serve as main raw materials; an environment-friendly catalyst and other auxiliary materials are added, the reaction and foaming are performed through a conventional polyurethane sponge production line at normal temperature, and the no-yellowing polyurethane sponge is obtained through a curing stage. The no-yellowing sponge can be obtained through the conventional polyurethane sponge production line at normal temperature, the raw materials do not need to be heated, existing equipment does not need to be modified, and the method has the advantages of small equipment investment and low energy consumption. In addition, since 4,4'-dicyclohexylmethane diisocyanate does not contain a benzene ring structure, obtained polyurethane sponge does not yellow, is excellent in aging resistance, oxidization resistance and illumination resistance and can be widely applied to the fields of shoe materials, furniture, electronics, printing supplies, aviation, automobiles, medical beauty, packaging, sports goods and articles for daily use.