The invention relates to a detection method of a short-circuit fault point of a high-voltage single-core cable. The method is used for determining a specific position of a fault point in a cable suffering from a short-circuit fault, and comprises steps of taking n sampling points in the cable; assuming that each sampling point suffers from a short-circuit fault and carrying out simulation; calculating the phase position difference of current of protection layers on two ends of the cable when each sampling point suffers from the short-circuit fault; carrying out fitting according to each phase position difference to obtain a relational expression between the fault point position and the phase position difference of a corresponding point suffering from the short-circuit fault of the cable; and when a short-circuit fault occurs in the cable, according to the relational expression between the fault point position and the phase position difference of the corresponding point suffering from the short-circuit fault, determining the specific position of the fault point suffering from the short-circuit fault. According to the invention, the specific position where the short-circuit fault occurs in a segment of cable can be quickly and precisely determined; precise positioning can be achieved; online monitoring is achieved; and the fault point can be timely found after the fault occurs.