Blending different kinds of rubber was one of the effective ways to improve the properties of products. By blending part of chloroprene rubber （CR） into EPDM rubber， the influence law of blending insulation properties was studied. The results show that， properties can be improved by blending CR with EPDM rubber. When the content of CR is no more than 30 parts by weight， the vulcanization properties，heat resistance and tensile properties of the blended rubber can be improved obviously. And the glass transition temperature， preparation technology and other basic characteristics of rubber blends do not change substantially.In addition， the ablation test results show that the addition of CR increases the deposition amount on the surface of aramid fiber after ablative substrate， which is beneficial to improve the ablative resistance of insulation.The application results show that the tensile strength and ablation performance of EPDM/CR blending insulation is better than that of the single EPDM rubber insulation.