The present invention provides a method for preparing 3-aminomethyl-3,5,5-trimethyl cyclohexylamine. The method comprises: a) reacting 3-cyano-3,5,5-trimethyl cyclohexanone with excess primary amine as well as removing the water generated from the reaction, so that IPN is substantially converted into imine compounds; b) in the presence of an ammonolysis catalyst, mixing the product of step a) with liquid ammonia, making the imine compound perform ammonolysis reaction to generate 3-cyano-3,5,5-trimethyl cyclohexylimine and the primary amine; and c) in the presence of hydrogen and a hydrogenation catalyst, hydrogenating 3-cyano-3,5,5-trimethyl cyclohexylimine obtained in step b) to obtain 3-aminomethyl-3,5,5-trimethyl cyclohexylamine. The method of the present invention avoids the generation of 3,5,5-trimethyl cyclohexanol and 3-aminomethyl-3,5,5-trimethyl cyclohexanol as the major by-products in the prior art, thereby improving the yield of 3-aminomethyl-3,5,5-trimethyl cyclohexylamine.