Disclosed is an inter-phase impedance setting calculation method considering arc light resistance influences. The inter-phase impedance setting calculation method considering the arc light resistance influences can obtain an inter-phase fault impedance expression as follows by taking BC phases of short circuits as an example and analyzing the influences of transition resistance Rg between the two phases through power system fault analysis. When a short circuit phenomenon occurs between the two phases due to the arc light resistance, an absolute value of the of measured impedance under the influences of the arc light resistance is expressed as another expression as follows. An inter-phase impedance setting calculation formula considering the arc light resistance influences is obtained by considering nominal voltage Ue as 100V, considering power supply fluctuation, calculation error and the like, and setting a confidence coefficient K as 1.5. The conclusion that a boundary can evade the influences of load impedance by drawing the positive sequence measured impedance of the short circuits between the two phases and the arc light resistance influences on an R-X complex plane. By analyzing the inter-phase impedance setting calculation method considering the arc light resistance influences from a perspective of power angles after a relation among an oscillation track, the power angles and setting impedance is drawn, the inter-phase impedance setting calculation method considering the arc light resistance influences can tolerate large power angle change when used to perform inter-phase impedance setting.