The invention provides a grounding wire, a testing system and a testing method. The grounding wire comprises two grounding components, and is characterized in that each grounding component comprises agrounding conductor and a connecting device; one end of the grounding conductor is connected with the corresponding connecting device, and the other end is used for being connected with detection equipment or electrical equipment; and the connecting devices are used for being connected with a grounding copper bar. According to the grounding wire, the testing system and the testing method providedby the invention, the power utilization safety of the electrical equipment can be ensured when the grounding wire is connected with the electrical equipment, the two grounding conductors can be directly connected with two input ends of the detection equipment when the grounding wire is connected with the detection equipment, thereby realizing resistance measurement, effectively reducing the detection difficulty, and improving the detection efficiency.