Using the neutral grounding method by the resistance in 110 kV system, it can limit the voltage sag and short circuit current when one-phase grounding fault occurred, but it will change the sequence of the network structure and parameters. This paper analyzes the size and distribution of zero sequence voltage and current when one-phase grounding fault occurred in the 110 kV resistance grounding system, and puts forward the grounding protection configuration setting principle of this system combining the power supplying characteristics of 110 kV distribution network. In a reforming substation as an example, the grounding protection of 110 kV lines and transformer have been set and calculated.