In this paper, a study on the design of the termination part for a 23kV superconducting cable is conducted. Also, the design of a spacer is derived in consideration of electrical and mechanical safety factors. In general, the termination part of a superconducting cable is filled with gaseous nitrogen (GN₂) and gaseous sulphur hexafluoride (SF<SUB>6</SUB>), and may have a temperature gradient from cryogenic to room temperature. Therefore, a design considering the dependency of dielectric characteristics on temperature should be conducted. In this study, the criterion of electric field intensity on the creepage discharge characteristics between a solid and gaseous insulation material according to several conditions is derived through dielectric experiments. Also, overall design of the termination part for a 23kV superconducting cable is proposed considering the mechanical as well as electrical safety factors.