Abstract: A long-distance high-voltage cable fault degree detection method. A cable fault positioning curve is obtained by using a frequency-domain reflection method, and a cable fault positioning compensation curve is determined by means of theoretical calculation in combination with the parameters of a frequency-domain incident signal, cable structure parameters, and characteristic parameters of each layer of materials of the field test; furthermore, a cable fault diagnosis curve is determined on the basis of the cable fault positioning curve and the cable fault positioning compensation curve, the severity of the fault is determined by means of the amplitude of a peak point of the cable fault diagnosis curve, and the accuracy of long-distance high-voltage cable fault degree diagnosis is effectively improved.