The invention provides a method for synthesizing trans-4-methylcyclohexylamine, and belongs to the technical field of chemical synthesis. The method comprises the following steps: taking cheap p-methylaniline as a raw material, taking supported ruthenium as a catalyst, adding an alkali metal promoter, and hydrogenating to obtain a 4-methylcyclohexylmethanamine cis-trans mixture; carrying out acidification to form salt, cis-trans separation, neutralization extraction and rectification on the 4-methylcyclohexylmethanamine cis-trans mixture to obtain the trans-4-methylcyclohexylamine product, wherein cis hydrochloride obtained through the cis-trans separation enters the process of cis-trans separation again through the steps of neutralization, extraction, rectification and transformation to recycle the raw material. The method has the beneficial effects that the catalyst is used repeatedly, so that the cost is reduced; the molar yield of the process of cis-trans separation reaches 42.4%,and the solvent is easy to recycle and reuse; the molar yield of the trans-4-methylcyclohexylamine reaches 65% or above, and is higher than the molar yield of the trans-4-methylcyclohexylamine synthesized by other processes reported in the literatures, the process is simple and controllable, and the quality of the product is stable.