The invention provides a pliers-shaped anti-interference current transformer and a transformer iron core grounding current testing system. The pliers-shaped anti-interference current transformer comprises a measuring current transformer body and a compensation current transformer body, wherein the measuring current transformer body is arranged on a transformer iron core grounding line in a sleeved mode and used for measuring the grounding current of a transformer iron core, the positive electrode of the measuring current transformer body is connected with the positive electrode of an ampere meter, and the negative electrode of the measuring current transformer body is connected with the negative electrode of the ampere meter. The compensation current transformer body is used for compensating the interference current of a leakage magnetic field, wherein the positive electrode of the compensation current transformer body is connected with the negative electrode of the measuring current transformer body, and the negative electrode of the compensation current transformer body is connected with the positive electrode of the measuring current transformer body. By means of the pliers-shaped anti-interference current transformer, interference generated by the leakage magnetic field can be balanced, and the accurate measurement of the grounding current of the transformer iron core can be realized.