DC plasma torch is reported as a technology that can be treated regardless of waste types because it can select transfer or non-transfer operation modes depending on the electrical conductivity of waste. Thanks to this characteristic, countries that operate nuclear power plants such as Switzerland, Japan, and Taiwan have developed high-power DC plasma torch to dispose of radioactive waste. And also in korea, a plasma torch is being developed to dispose of radioactive waste. This study was conducted to investigate the characteristics of the reverse polarity plasma torch according to the conditions of interelectrodes. The inter-electrodes of plasma torch used in the study was designed to be 25, 37 mm in diameter and 180 to 400 mm in length. As a result of the test, it was confirmed that the smaller the diameter and the longer the length of the inter-electrode, the more advantageous it was to achieve a high output power. And it was confirmed that the power torch would be 500 kW when the diameter of the inter-electrode was 25 mm, the length was 400 mm, and the current was 500 A.