A grounding resistance measurement apparatus electrically connected between an equipment input terminal (Sc) providing an AC power source and an equipment grounding point (PE), and configured to measure a grounding resistance (Rg) between the equipment grounding point (PE) and a power grounding point (PEs), the grounding resistance measurement apparatus comprising: a DC power generation circuit electrically connected to the equipment input terminal (Sc) and the equipment grounding point (PE), and configured to receive the AC power source and convert the AC power source into a DC power source; the DC power source configured to produce a DC resistance voltage (V dc_Rg ) across the grounding resistance (Rg) and a DC resistance current (I dc_Rg ) flowing through the grounding resistance (Rg), the DC power generation circuit is a DC voltage generation circuit or a DC current generation circuit; and a DC voltage detection circuit electrically connected to the equipment input terminal (Sc) and the equipment grounding point (PE), and configured to measure a DC voltage difference between the equipment input terminal (Sc) and the equipment grounding point (PE); wherein the DC voltage difference between the equipment input terminal (Sc) and the equipment grounding point (PE) is equal to the DC resistance voltage (V dc_Rg ) across the grounding resistance (Rg) according to a characteristic of the zero DC component in an AC power loop, and wherein the grounding resistance (Rg) is calculated according to the DC resistance voltage (Vdc_Rg) and the DC resistance current (Idc_Rg) if the DC power generation circuit is the DC current generation circuit, or wherein the grounding resistance (Rg) is calculated by a voltage-dividing theory if the DC power generation circuit is the DC voltage generation circuit. a DC power generation circuit electrically connected to the equipment input terminal (Sc) and the equipment grounding point (PE), and configured to receive the AC power source and convert the AC power source into a DC power source; the DC power source configured to produce a DC resistance voltage (V dc_Rg ) across the grounding resistance (Rg) and a DC resistance current (I dc_Rg ) flowing through the grounding resistance (Rg), the DC power generation circuit is a DC voltage generation circuit or a DC current generation circuit; and a DC voltage detection circuit electrically connected to the equipment input terminal (Sc) and the equipment grounding point (PE), and configured to measure a DC voltage difference between the equipment input terminal (Sc) and the equipment grounding point (PE); wherein the DC voltage difference between the equipment input terminal (Sc) and the equipment grounding point (PE) is equal to the DC resistance voltage (V dc_Rg ) across the grounding resistance (Rg) according to a characteristic of the zero DC component in an AC power loop, and wherein the grounding resistance (Rg) is calculated according to the DC resistance voltage (Vdc_Rg) and the DC resistance current (Idc_Rg) if the DC power generation circuit is the DC current generation circuit, or wherein the grounding resistance (Rg) is calculated by a voltage-dividing theory if the DC power generation circuit is the DC voltage generation circuit. <EOS>