Abstract: In order to solve the problem of low accuracy of fault detection for high resistance grounding fault, especially arc high resistance grounding fault, this paper constructed a new characteristic parameter of fault diagnosis by injecting a selected active current increment. A new method of detecting high resistance grounding fault in distribution network was proposed, especially for arc high resistance grounding fault. In practical application, only by injecting the selected current increment into the distribution network and measuring the variation of zero sequence voltage and line zero sequence current, the insulation parameters of system and line can be measured; the grounding fault judgment and fault degree tracking monitoring, fault phase selection and line selection can be realized. The method can eliminate the influence of active injection current regulation, asymmetric distribution parameters of power grid, and inductive component of grounding arc on the detection results, and therefore it is easy to operate and realize. The simulation and fault simulation experiments prove the effectiveness of the method, which provides a theoretical basis for the rapid and safe disposal of arc high resistance grounding fault in distribution network.