The invention provides a method for preparing 1,4-cyclohexanedimethanol from waste PET (polyethylene glycol terephthalate) degradation monomer diethylene glycol terephthalate, relating to the field of high-valued utilization and hydrogenation reduction of macromolecular compound degradation products. 1,4-cyclohexanedimethanol is prepared from the waste PET degradation monomer diethylene glycol terephthalate as raw materials by adopting a two-step hydrogenation process. The method comprises the following steps: firstly, performing benzene ring hydrogenation under the catalytic action of Pd/C to obtain an intermediate product 1,4-diethylene glycol cyclohexanedicarboxylate; secondly, reducing ester group on a side chain into alcohol group under the catalytic action of a copper chromium catalyst by taking a hydrogenation product in the first step as a raw material to obtain 1,4-cyclohexanedimethanol. According to the method, the waste PET degradation monomers are converted into the high-valued product, namely 1,4-cyclohexanedimethanol; the raw material cost is reduced and a new direction is provided for recycling of waste PET resources. The method has important meaning on resources sustainable development.