Abstract: In the distribution grid of large cities, the wide application of power cables plays an important role in the development of urban power grids. This paper introduces the application and basic principle of the partial discharge detection technology of the oscillating wave in the distribution network cable, and selects two cases of the partial discharge defects in 35kV cable joints with different processes which were found in the national sports meeting in 2017. The causes of partial discharge, partial discharge initiation voltage and partial discharge capacity are compared and analyzed. It is found that the process has an obvious influence on the type of partial discharge and the parameters of the partial discharge. It provides a reference for the popularization and application of the partial discharge detection technology and the scientific evaluation of the defect state.