The invention discloses a synthesizing method for N,N,N'-trimethyl-N'-ethoxyl-ethidene diamin.The synthesizing method comprises the following steps that firstly, synthesizing is carried out, wherein ethoxyl ethylenediamine, methanal substances, a catalyst and hydrogen are added into an autoclave to carry out a reaction in a sealed state with the reaction temperature ranging from 80 DEG C to 120 DEG C, the reaction pressure regulated with hydrogen to be 0-3 MPa and the reaction time ranging from 3 h to 7 h, the autoclave is opened after the reaction is finished, reaction liquor is filtered, and filter liquor is collected; secondly, separating is carried out, wherein the filter liquor obtained in the first step is subjected to atmospheric distillation to remove water, vacuum distillation is carried out, and N,N,N'-trimethyl-N'-ethoxyl-ethidene diamin is obtained.