For XLPE cables, partial discharge can detect various insulation defects, However, when the partial discharge pulse propagates in the cable, the pulse waveform changes due to attenuation.A thorough analysis of the change of pulse waveform when cable partial discharge pulse propagates and the influence of different coupling bandwidths on signal detection is discussed.It is concluded that when cable partial discharge occurs, the amplitude of pulse signal follows.The increase of propagation distance decreases rapidly, but the attenuation amplitude of apparent discharge is relatively small; at the same time, broadband coupling has higher sensitivity, but its charge calibration curve error is larger and it will lead to the decrease of signal-to-noise ratio; although narrowband coupling can obtain more accurate charge calibration curve, it will cause pulse waveforms to overlap, affecting fault location.