The utility model provides a low-voltage phase line grounding remote alarm for a 10-20kV transformer, comprising a grounding current signal collection circuit, a signal judgment circuit, a switch trip circuit and an alarm circuit, wherein the grounding current signal collection circuit is connected with the signal judgment circuit which is connected with the switch trip circuit and the alarm circuit; when a power low-voltage phase line is grounded, a leakage protector acts to cause a power supply to trip and simultaneously to make a remote alarm, thereby realizing on-line monitoring alarm and timely reporting an accident to on-duty staff, so that a maintainer can arrive at the spot at the very first time for timely repair, thereby shortening the treatment time of the accident, reducing the labor intensity of workers, improving the power supply amount and increasing the benefits of an enterprise and the society; meanwhile, the low-voltage phase line grounding remote alarm for the 10-20kV transformer plays the role of actively promoting the intelligent technical development of a power distribution system; and the alarm has the advantages of scientific and reasonable design, low cost, simple structure, smart conception and simple and convenient use.