A method for preparing N,N′-bis(2-cyanoethyl-1,2-ethylenediamine involves using glycol ether as a catalyst for synthesis reaction in which ethylenediamine and acrylonitrile at a molar ratio of 1:1.9-2.1 are reactant that react at 20-70°C to prepare N,N′-bis(2-cyanoethyl)-1,2-ethylenediamine; the method improves the yield to 98.15-98.98%; and the used glycol ether may be filtered and recycled, thereby saving costs and reducing environmental pollution.