The attenuation characteristics of a partial discharge (PD) pulse propagating in a long-distance power cable is always a concern for PD detection. The high frequency attenuation of the symmetric PD pulse waveform has been previously well modeled, and the approximate solution concerning the asymmetric pulse has also been discussed. In this paper, a method to calculate the attenuation characteristics of the asymmetric PD calibration pulse is proposed, based on the measured attenuation constant of sinusoidal wave signals propagating in different lengths of 110 kV cross-linked polyethylene (XLPE) cables. The amplitude, pulse width, and area of the attenuated calibration pulse are measured in the field to verify the method. The results indicate that the product of the exponential function and Gaussian error function can be used to describe the attenuation characteristics of the calibration pulse, and the area under the pulse curve is unchanged.