Research on the mechanical properties of the dielectric paper and mini-model cable are important for optimum electrical insulation design of HTS cable, because the HTS cable experience of mechanical stress, such as tensile and bending stress. Also, it is operated at cryogenic temperature. Therefore, this paper discusses the experiment results on the AC and lighting impulse breakdown characteristics, partial discharge inception and extinction characteristics, and external shape change of the insulation layer according to bending strain of the mini-model cable.