During the production of 1,2-propanediamine with isopropandamine as raw material , the bottom residues after distillation are the mixture on isopropanolamine, 1, 2-propanediamine and 2,5-dimethyl piperazine and 2, 6 - dimethyl i.e.the mixture of piperazine, it is difficult to by a simple distillation method.The methods of separating 1,2-propanediamine and isopropanolamine  from the mixture out of the methods were discusses,including rotary evaporation, chemical separation, azeotropic distillation, and azeotropic distillation adsorptive separation azeotropic distillation method. The results show that the separation result isn’t ideal by rotary evaporation and chemical separation method by azeotropic distillation and adsorptive separation azeotropic distillation method of 1,2-propane diamine and isopropanolamine can be separated from the mixture of isopropanol amine out; the separetion is the best under mass ratio of the mixture of isopropanol amine out and waater of 1∶ 2, and with zsm-5 as adsorbentbest.