Abstract: The load characteristics of the power system lead to the result that power distribution cables operate under continuous thermal cyclings. Field experiences show that accessories' failure caused by interface discharge always occurs when cable operating temperature change due to the load changes or ambient temperature differences, while the study on the discharge characteristics under such circumstances is still not in depth. Therefore, this paper uses prefabricated sensors for interface pressure measurement, and firstly conducts preaging experiments of 50 thermal cyclings on the cable accessories with semiconductive protrusion defects. Then, by setting up a comparison sample, the changes of the surface pressure and temperature of the accessories are compared with the partial discharge (PD) features under the single thermal cycling. The experimental results show that the partial discharge at the interface of the cable accessories would go through four stages during thermal cycling, in which the PD excitation would appear while temperature rises and declines, and PD would get suppressed while the interface state is stable. This phenomenon happens due to the interaction of two factors, the interface temperature and the interface pressure during the process. Finally, from the perspective of the material properties of silicone rubber and the interfacial cavity discharge, the partial discharge behavior characteristics of the accessory interface during a single thermal cycling are dynamically explained.