The invention relates to a high-resistance ground fault positioning method and system. According to a fault line selection result, projection components of transient zero-sequence currents of each monitoring point at upstream and downstream positions of each section of a fault feed line on bus transient zero-sequence voltages are calculated, amplitude sizes of the projection components of the transient zero-sequence currents of each monitoring point are compared, a plurality of monitoring points with largest projection component amplitude are selected, the area of the plurality of monitoring points is taken as a fault candidate section, and a polarity relation is determined; if the two have the same polarity, the section is considered as a sound section; and if the two have opposite polarities, the section is considered as a fault section. The method and system solve the problem of difficulty in positioning a high-resistance ground fault in a low-current grounding system and have a wide actual application value.